diff --git a/man/import.go b/man/import.go
index bc117bdcfb..76cb75f473 100644
--- a/man/import.go
+++ b/man/import.go
@@ -4,4 +4,4 @@ package main
 
 // Not used, but required for generating other man pages.
 // Import it here so that the package is included by vndr.
-import _ "github.com/cpuguy83/go-md2man"
+import _ "github.com/cpuguy83/go-md2man/v2"
diff --git a/man/md2man-all.sh b/man/md2man-all.sh
index 46c7b8f08e..eb0bc6366a 100755
--- a/man/md2man-all.sh
+++ b/man/md2man-all.sh
@@ -18,5 +18,5 @@ for FILE in *.md; do
 		continue
 	fi
 	mkdir -p "./man${num}"
-	go-md2man -in "$FILE" -out "./man${num}/${name}"
+	md2man -in "$FILE" -out "./man${num}/${name}"
 done
diff --git a/scripts/docs/generate-man.sh b/scripts/docs/generate-man.sh
index 7412e5baa5..299c422321 100755
--- a/scripts/docs/generate-man.sh
+++ b/scripts/docs/generate-man.sh
@@ -4,7 +4,8 @@ set -eu -o pipefail
 
 mkdir -p ./man/man1
 
-go install ./vendor/github.com/cpuguy83/go-md2man
+# yay, go install creates a binary named "v2" ¯\_(ツ)_/¯
+go build -o "/go/bin/md2man" ./vendor/github.com/cpuguy83/go-md2man/v2
 
 # Generate man pages from cobra commands
 go build -o /tmp/gen-manpages github.com/docker/cli/man
diff --git a/vendor.conf b/vendor.conf
index d879e85183..a45dbf70ad 100755
--- a/vendor.conf
+++ b/vendor.conf
@@ -7,7 +7,7 @@ github.com/containerd/containerd                    4d242818bf55542e5d7876ca276f
 github.com/containerd/continuity                    26c1120b8d4107d2471b93ad78ef7ce1fc84c4c4
 github.com/containerd/cgroups                       44306b6a1d46985d916b48b4199f93a378af314f
 github.com/coreos/etcd                              d57e8b8d97adfc4a6c224fe116714bf1a1f3beb9 # v3.3.12
-github.com/cpuguy83/go-md2man                       20f5889cbdc3c73dbd2862796665e7c465ade7d1 # v1.0.8
+github.com/cpuguy83/go-md2man/v2                    f79a8a8ca69da163eee19ab442bedad7a35bba5a # v2.0.0
 github.com/creack/pty                               3a6a957789163cacdfe0e291617a1c8e80612c11 # v1.1.9
 github.com/davecgh/go-spew                          8991bc29aa16c548c550c7ff78260e27b9ab7c73 # v1.1.1
 github.com/docker/compose-on-kubernetes             78e6a00beda64ac8ccb9fec787e601fe2ce0d5bb # v0.5.0-alpha1
@@ -60,10 +60,10 @@ github.com/prometheus/client_golang                 c5b7fccd204277076155f10851da
 github.com/prometheus/client_model                  6f3806018612930941127f2a7c6c453ba2c527d2
 github.com/prometheus/common                        7600349dcfe1abd18d72d3a1770870d9800a7801
 github.com/prometheus/procfs                        7d6f385de8bea29190f15ba9931442a0eaef9af7
-github.com/russross/blackfriday                     1d6b8e9301e720b08a8938b8c25c018285885438
-github.com/shurcooL/sanitized_anchor_name           10ef21a441db47d8b13ebcc5fd2310f636973c77
+github.com/russross/blackfriday/v2                  d3b5b032dc8e8927d31a5071b56e14c89f045135 # v2.0.1
+github.com/shurcooL/sanitized_anchor_name           7bfe4c7ecddb3666a94b053b422cdd8f5aaa3615 # v1.0.0
 github.com/sirupsen/logrus                          60c74ad9be0d874af0ab0daef6ab07c5c5911f0d # v1.6.0
-github.com/spf13/cobra                              ef82de70bb3f60c65fb8eebacbb2d122ef517385 # v0.0.3
+github.com/spf13/cobra                              a684a6d7f5e37385d954dd3b5a14fc6912c6ab9d # v1.0.0
 github.com/spf13/pflag                              2e9d26c8c37aae03e3f9d4e90b7116f5accb7cab # v1.0.5
 github.com/theupdateframework/notary                d6e1431feb32348e0650bf7551ac5cffd01d857b # v0.6.1
 github.com/tonistiigi/fsutil                        c2c7d7b0e1441705cd802e5699c0a10b1dfe39fd
diff --git a/vendor/github.com/cpuguy83/go-md2man/README.md b/vendor/github.com/cpuguy83/go-md2man/README.md
deleted file mode 100644
index 29ed7c9e9f..0000000000
--- a/vendor/github.com/cpuguy83/go-md2man/README.md
+++ /dev/null
@@ -1,21 +0,0 @@
-go-md2man
-=========
-
-** Work in Progress **
-This still needs a lot of help to be complete, or even usable!
-
-Uses blackfriday to process markdown into man pages.
-
-### Usage
-
-./md2man -in /path/to/markdownfile.md -out /manfile/output/path
-
-### How to contribute
-
-We use [dep](https://github.com/golang/dep/) for vendoring Go packages.
-See dep documentation for how to update.
-
-### TODO
-
-- Needs oh so much testing love
-- Look into blackfriday's 2.0 API
diff --git a/vendor/github.com/cpuguy83/go-md2man/md2man/md2man.go b/vendor/github.com/cpuguy83/go-md2man/md2man/md2man.go
deleted file mode 100644
index af62279a61..0000000000
--- a/vendor/github.com/cpuguy83/go-md2man/md2man/md2man.go
+++ /dev/null
@@ -1,20 +0,0 @@
-package md2man
-
-import (
-	"github.com/russross/blackfriday"
-)
-
-// Render converts a markdown document into a roff formatted document.
-func Render(doc []byte) []byte {
-	renderer := RoffRenderer(0)
-	extensions := 0
-	extensions |= blackfriday.EXTENSION_NO_INTRA_EMPHASIS
-	extensions |= blackfriday.EXTENSION_TABLES
-	extensions |= blackfriday.EXTENSION_FENCED_CODE
-	extensions |= blackfriday.EXTENSION_AUTOLINK
-	extensions |= blackfriday.EXTENSION_SPACE_HEADERS
-	extensions |= blackfriday.EXTENSION_FOOTNOTES
-	extensions |= blackfriday.EXTENSION_TITLEBLOCK
-
-	return blackfriday.Markdown(doc, renderer, extensions)
-}
diff --git a/vendor/github.com/cpuguy83/go-md2man/md2man/roff.go b/vendor/github.com/cpuguy83/go-md2man/md2man/roff.go
deleted file mode 100644
index 8c29ec6873..0000000000
--- a/vendor/github.com/cpuguy83/go-md2man/md2man/roff.go
+++ /dev/null
@@ -1,285 +0,0 @@
-package md2man
-
-import (
-	"bytes"
-	"fmt"
-	"html"
-	"strings"
-
-	"github.com/russross/blackfriday"
-)
-
-type roffRenderer struct {
-	ListCounters []int
-}
-
-// RoffRenderer creates a new blackfriday Renderer for generating roff documents
-// from markdown
-func RoffRenderer(flags int) blackfriday.Renderer {
-	return &roffRenderer{}
-}
-
-func (r *roffRenderer) GetFlags() int {
-	return 0
-}
-
-func (r *roffRenderer) TitleBlock(out *bytes.Buffer, text []byte) {
-	out.WriteString(".TH ")
-
-	splitText := bytes.Split(text, []byte("\n"))
-	for i, line := range splitText {
-		line = bytes.TrimPrefix(line, []byte("% "))
-		if i == 0 {
-			line = bytes.Replace(line, []byte("("), []byte("\" \""), 1)
-			line = bytes.Replace(line, []byte(")"), []byte("\" \""), 1)
-		}
-		line = append([]byte("\""), line...)
-		line = append(line, []byte("\" ")...)
-		out.Write(line)
-	}
-	out.WriteString("\n")
-
-	// disable hyphenation
-	out.WriteString(".nh\n")
-	// disable justification (adjust text to left margin only)
-	out.WriteString(".ad l\n")
-}
-
-func (r *roffRenderer) BlockCode(out *bytes.Buffer, text []byte, lang string) {
-	out.WriteString("\n.PP\n.RS\n\n.nf\n")
-	escapeSpecialChars(out, text)
-	out.WriteString("\n.fi\n.RE\n")
-}
-
-func (r *roffRenderer) BlockQuote(out *bytes.Buffer, text []byte) {
-	out.WriteString("\n.PP\n.RS\n")
-	out.Write(text)
-	out.WriteString("\n.RE\n")
-}
-
-func (r *roffRenderer) BlockHtml(out *bytes.Buffer, text []byte) { // nolint: golint
-	out.Write(text)
-}
-
-func (r *roffRenderer) Header(out *bytes.Buffer, text func() bool, level int, id string) {
-	marker := out.Len()
-
-	switch {
-	case marker == 0:
-		// This is the doc header
-		out.WriteString(".TH ")
-	case level == 1:
-		out.WriteString("\n\n.SH ")
-	case level == 2:
-		out.WriteString("\n.SH ")
-	default:
-		out.WriteString("\n.SS ")
-	}
-
-	if !text() {
-		out.Truncate(marker)
-		return
-	}
-}
-
-func (r *roffRenderer) HRule(out *bytes.Buffer) {
-	out.WriteString("\n.ti 0\n\\l'\\n(.lu'\n")
-}
-
-func (r *roffRenderer) List(out *bytes.Buffer, text func() bool, flags int) {
-	marker := out.Len()
-	r.ListCounters = append(r.ListCounters, 1)
-	out.WriteString("\n.RS\n")
-	if !text() {
-		out.Truncate(marker)
-		return
-	}
-	r.ListCounters = r.ListCounters[:len(r.ListCounters)-1]
-	out.WriteString("\n.RE\n")
-}
-
-func (r *roffRenderer) ListItem(out *bytes.Buffer, text []byte, flags int) {
-	if flags&blackfriday.LIST_TYPE_ORDERED != 0 {
-		out.WriteString(fmt.Sprintf(".IP \"%3d.\" 5\n", r.ListCounters[len(r.ListCounters)-1]))
-		r.ListCounters[len(r.ListCounters)-1]++
-	} else {
-		out.WriteString(".IP \\(bu 2\n")
-	}
-	out.Write(text)
-	out.WriteString("\n")
-}
-
-func (r *roffRenderer) Paragraph(out *bytes.Buffer, text func() bool) {
-	marker := out.Len()
-	out.WriteString("\n.PP\n")
-	if !text() {
-		out.Truncate(marker)
-		return
-	}
-	if marker != 0 {
-		out.WriteString("\n")
-	}
-}
-
-func (r *roffRenderer) Table(out *bytes.Buffer, header []byte, body []byte, columnData []int) {
-	out.WriteString("\n.TS\nallbox;\n")
-
-	maxDelims := 0
-	lines := strings.Split(strings.TrimRight(string(header), "\n")+"\n"+strings.TrimRight(string(body), "\n"), "\n")
-	for _, w := range lines {
-		curDelims := strings.Count(w, "\t")
-		if curDelims > maxDelims {
-			maxDelims = curDelims
-		}
-	}
-	out.Write([]byte(strings.Repeat("l ", maxDelims+1) + "\n"))
-	out.Write([]byte(strings.Repeat("l ", maxDelims+1) + ".\n"))
-	out.Write(header)
-	if len(header) > 0 {
-		out.Write([]byte("\n"))
-	}
-
-	out.Write(body)
-	out.WriteString("\n.TE\n")
-}
-
-func (r *roffRenderer) TableRow(out *bytes.Buffer, text []byte) {
-	if out.Len() > 0 {
-		out.WriteString("\n")
-	}
-	out.Write(text)
-}
-
-func (r *roffRenderer) TableHeaderCell(out *bytes.Buffer, text []byte, align int) {
-	if out.Len() > 0 {
-		out.WriteString("\t")
-	}
-	if len(text) == 0 {
-		text = []byte{' '}
-	}
-	out.Write([]byte("\\fB\\fC" + string(text) + "\\fR"))
-}
-
-func (r *roffRenderer) TableCell(out *bytes.Buffer, text []byte, align int) {
-	if out.Len() > 0 {
-		out.WriteString("\t")
-	}
-	if len(text) > 30 {
-		text = append([]byte("T{\n"), text...)
-		text = append(text, []byte("\nT}")...)
-	}
-	if len(text) == 0 {
-		text = []byte{' '}
-	}
-	out.Write(text)
-}
-
-func (r *roffRenderer) Footnotes(out *bytes.Buffer, text func() bool) {
-
-}
-
-func (r *roffRenderer) FootnoteItem(out *bytes.Buffer, name, text []byte, flags int) {
-
-}
-
-func (r *roffRenderer) AutoLink(out *bytes.Buffer, link []byte, kind int) {
-	out.WriteString("\n\\[la]")
-	out.Write(link)
-	out.WriteString("\\[ra]")
-}
-
-func (r *roffRenderer) CodeSpan(out *bytes.Buffer, text []byte) {
-	out.WriteString("\\fB\\fC")
-	escapeSpecialChars(out, text)
-	out.WriteString("\\fR")
-}
-
-func (r *roffRenderer) DoubleEmphasis(out *bytes.Buffer, text []byte) {
-	out.WriteString("\\fB")
-	out.Write(text)
-	out.WriteString("\\fP")
-}
-
-func (r *roffRenderer) Emphasis(out *bytes.Buffer, text []byte) {
-	out.WriteString("\\fI")
-	out.Write(text)
-	out.WriteString("\\fP")
-}
-
-func (r *roffRenderer) Image(out *bytes.Buffer, link []byte, title []byte, alt []byte) {
-}
-
-func (r *roffRenderer) LineBreak(out *bytes.Buffer) {
-	out.WriteString("\n.br\n")
-}
-
-func (r *roffRenderer) Link(out *bytes.Buffer, link []byte, title []byte, content []byte) {
-	out.Write(content)
-	r.AutoLink(out, link, 0)
-}
-
-func (r *roffRenderer) RawHtmlTag(out *bytes.Buffer, tag []byte) { // nolint: golint
-	out.Write(tag)
-}
-
-func (r *roffRenderer) TripleEmphasis(out *bytes.Buffer, text []byte) {
-	out.WriteString("\\s+2")
-	out.Write(text)
-	out.WriteString("\\s-2")
-}
-
-func (r *roffRenderer) StrikeThrough(out *bytes.Buffer, text []byte) {
-}
-
-func (r *roffRenderer) FootnoteRef(out *bytes.Buffer, ref []byte, id int) {
-
-}
-
-func (r *roffRenderer) Entity(out *bytes.Buffer, entity []byte) {
-	out.WriteString(html.UnescapeString(string(entity)))
-}
-
-func (r *roffRenderer) NormalText(out *bytes.Buffer, text []byte) {
-	escapeSpecialChars(out, text)
-}
-
-func (r *roffRenderer) DocumentHeader(out *bytes.Buffer) {
-}
-
-func (r *roffRenderer) DocumentFooter(out *bytes.Buffer) {
-}
-
-func needsBackslash(c byte) bool {
-	for _, r := range []byte("-_&\\~") {
-		if c == r {
-			return true
-		}
-	}
-	return false
-}
-
-func escapeSpecialChars(out *bytes.Buffer, text []byte) {
-	for i := 0; i < len(text); i++ {
-		// escape initial apostrophe or period
-		if len(text) >= 1 && (text[0] == '\'' || text[0] == '.') {
-			out.WriteString("\\&")
-		}
-
-		// directly copy normal characters
-		org := i
-
-		for i < len(text) && !needsBackslash(text[i]) {
-			i++
-		}
-		if i > org {
-			out.Write(text[org:i])
-		}
-
-		// escape a character
-		if i >= len(text) {
-			break
-		}
-		out.WriteByte('\\')
-		out.WriteByte(text[i])
-	}
-}
diff --git a/vendor/github.com/cpuguy83/go-md2man/LICENSE.md b/vendor/github.com/cpuguy83/go-md2man/v2/LICENSE.md
similarity index 100%
rename from vendor/github.com/cpuguy83/go-md2man/LICENSE.md
rename to vendor/github.com/cpuguy83/go-md2man/v2/LICENSE.md
diff --git a/vendor/github.com/cpuguy83/go-md2man/v2/README.md b/vendor/github.com/cpuguy83/go-md2man/v2/README.md
new file mode 100644
index 0000000000..0e30d34148
--- /dev/null
+++ b/vendor/github.com/cpuguy83/go-md2man/v2/README.md
@@ -0,0 +1,15 @@
+go-md2man
+=========
+
+Converts markdown into roff (man pages).
+
+Uses blackfriday to process markdown into man pages.
+
+### Usage
+
+./md2man -in /path/to/markdownfile.md -out /manfile/output/path
+
+### How to contribute
+
+We use go modules to manage dependencies.
+As such you must be using at lest go1.11.
diff --git a/vendor/github.com/cpuguy83/go-md2man/v2/go.mod b/vendor/github.com/cpuguy83/go-md2man/v2/go.mod
new file mode 100644
index 0000000000..ae5345814b
--- /dev/null
+++ b/vendor/github.com/cpuguy83/go-md2man/v2/go.mod
@@ -0,0 +1,9 @@
+module github.com/cpuguy83/go-md2man/v2
+
+go 1.12
+
+require (
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/russross/blackfriday/v2 v2.0.1
+	github.com/shurcooL/sanitized_anchor_name v1.0.0 // indirect
+)
diff --git a/vendor/github.com/cpuguy83/go-md2man/md2man.go b/vendor/github.com/cpuguy83/go-md2man/v2/md2man.go
similarity index 95%
rename from vendor/github.com/cpuguy83/go-md2man/md2man.go
rename to vendor/github.com/cpuguy83/go-md2man/v2/md2man.go
index c35dd3352e..6078864a3c 100644
--- a/vendor/github.com/cpuguy83/go-md2man/md2man.go
+++ b/vendor/github.com/cpuguy83/go-md2man/v2/md2man.go
@@ -6,7 +6,7 @@ import (
 	"io/ioutil"
 	"os"
 
-	"github.com/cpuguy83/go-md2man/md2man"
+	"github.com/cpuguy83/go-md2man/v2/md2man"
 )
 
 var inFilePath = flag.String("in", "", "Path to file to be processed (default: stdin)")
diff --git a/vendor/github.com/cpuguy83/go-md2man/v2/md2man/md2man.go b/vendor/github.com/cpuguy83/go-md2man/v2/md2man/md2man.go
new file mode 100644
index 0000000000..b480056734
--- /dev/null
+++ b/vendor/github.com/cpuguy83/go-md2man/v2/md2man/md2man.go
@@ -0,0 +1,14 @@
+package md2man
+
+import (
+	"github.com/russross/blackfriday/v2"
+)
+
+// Render converts a markdown document into a roff formatted document.
+func Render(doc []byte) []byte {
+	renderer := NewRoffRenderer()
+
+	return blackfriday.Run(doc,
+		[]blackfriday.Option{blackfriday.WithRenderer(renderer),
+			blackfriday.WithExtensions(renderer.GetExtensions())}...)
+}
diff --git a/vendor/github.com/cpuguy83/go-md2man/v2/md2man/roff.go b/vendor/github.com/cpuguy83/go-md2man/v2/md2man/roff.go
new file mode 100644
index 0000000000..0668a66cf7
--- /dev/null
+++ b/vendor/github.com/cpuguy83/go-md2man/v2/md2man/roff.go
@@ -0,0 +1,345 @@
+package md2man
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	"github.com/russross/blackfriday/v2"
+)
+
+// roffRenderer implements the blackfriday.Renderer interface for creating
+// roff format (manpages) from markdown text
+type roffRenderer struct {
+	extensions   blackfriday.Extensions
+	listCounters []int
+	firstHeader  bool
+	defineTerm   bool
+	listDepth    int
+}
+
+const (
+	titleHeader      = ".TH "
+	topLevelHeader   = "\n\n.SH "
+	secondLevelHdr   = "\n.SH "
+	otherHeader      = "\n.SS "
+	crTag            = "\n"
+	emphTag          = "\\fI"
+	emphCloseTag     = "\\fP"
+	strongTag        = "\\fB"
+	strongCloseTag   = "\\fP"
+	breakTag         = "\n.br\n"
+	paraTag          = "\n.PP\n"
+	hruleTag         = "\n.ti 0\n\\l'\\n(.lu'\n"
+	linkTag          = "\n\\[la]"
+	linkCloseTag     = "\\[ra]"
+	codespanTag      = "\\fB\\fC"
+	codespanCloseTag = "\\fR"
+	codeTag          = "\n.PP\n.RS\n\n.nf\n"
+	codeCloseTag     = "\n.fi\n.RE\n"
+	quoteTag         = "\n.PP\n.RS\n"
+	quoteCloseTag    = "\n.RE\n"
+	listTag          = "\n.RS\n"
+	listCloseTag     = "\n.RE\n"
+	arglistTag       = "\n.TP\n"
+	tableStart       = "\n.TS\nallbox;\n"
+	tableEnd         = ".TE\n"
+	tableCellStart   = "T{\n"
+	tableCellEnd     = "\nT}\n"
+)
+
+// NewRoffRenderer creates a new blackfriday Renderer for generating roff documents
+// from markdown
+func NewRoffRenderer() *roffRenderer { // nolint: golint
+	var extensions blackfriday.Extensions
+
+	extensions |= blackfriday.NoIntraEmphasis
+	extensions |= blackfriday.Tables
+	extensions |= blackfriday.FencedCode
+	extensions |= blackfriday.SpaceHeadings
+	extensions |= blackfriday.Footnotes
+	extensions |= blackfriday.Titleblock
+	extensions |= blackfriday.DefinitionLists
+	return &roffRenderer{
+		extensions: extensions,
+	}
+}
+
+// GetExtensions returns the list of extensions used by this renderer implementation
+func (r *roffRenderer) GetExtensions() blackfriday.Extensions {
+	return r.extensions
+}
+
+// RenderHeader handles outputting the header at document start
+func (r *roffRenderer) RenderHeader(w io.Writer, ast *blackfriday.Node) {
+	// disable hyphenation
+	out(w, ".nh\n")
+}
+
+// RenderFooter handles outputting the footer at the document end; the roff
+// renderer has no footer information
+func (r *roffRenderer) RenderFooter(w io.Writer, ast *blackfriday.Node) {
+}
+
+// RenderNode is called for each node in a markdown document; based on the node
+// type the equivalent roff output is sent to the writer
+func (r *roffRenderer) RenderNode(w io.Writer, node *blackfriday.Node, entering bool) blackfriday.WalkStatus {
+
+	var walkAction = blackfriday.GoToNext
+
+	switch node.Type {
+	case blackfriday.Text:
+		r.handleText(w, node, entering)
+	case blackfriday.Softbreak:
+		out(w, crTag)
+	case blackfriday.Hardbreak:
+		out(w, breakTag)
+	case blackfriday.Emph:
+		if entering {
+			out(w, emphTag)
+		} else {
+			out(w, emphCloseTag)
+		}
+	case blackfriday.Strong:
+		if entering {
+			out(w, strongTag)
+		} else {
+			out(w, strongCloseTag)
+		}
+	case blackfriday.Link:
+		if !entering {
+			out(w, linkTag+string(node.LinkData.Destination)+linkCloseTag)
+		}
+	case blackfriday.Image:
+		// ignore images
+		walkAction = blackfriday.SkipChildren
+	case blackfriday.Code:
+		out(w, codespanTag)
+		escapeSpecialChars(w, node.Literal)
+		out(w, codespanCloseTag)
+	case blackfriday.Document:
+		break
+	case blackfriday.Paragraph:
+		// roff .PP markers break lists
+		if r.listDepth > 0 {
+			return blackfriday.GoToNext
+		}
+		if entering {
+			out(w, paraTag)
+		} else {
+			out(w, crTag)
+		}
+	case blackfriday.BlockQuote:
+		if entering {
+			out(w, quoteTag)
+		} else {
+			out(w, quoteCloseTag)
+		}
+	case blackfriday.Heading:
+		r.handleHeading(w, node, entering)
+	case blackfriday.HorizontalRule:
+		out(w, hruleTag)
+	case blackfriday.List:
+		r.handleList(w, node, entering)
+	case blackfriday.Item:
+		r.handleItem(w, node, entering)
+	case blackfriday.CodeBlock:
+		out(w, codeTag)
+		escapeSpecialChars(w, node.Literal)
+		out(w, codeCloseTag)
+	case blackfriday.Table:
+		r.handleTable(w, node, entering)
+	case blackfriday.TableCell:
+		r.handleTableCell(w, node, entering)
+	case blackfriday.TableHead:
+	case blackfriday.TableBody:
+	case blackfriday.TableRow:
+		// no action as cell entries do all the nroff formatting
+		return blackfriday.GoToNext
+	default:
+		fmt.Fprintln(os.Stderr, "WARNING: go-md2man does not handle node type "+node.Type.String())
+	}
+	return walkAction
+}
+
+func (r *roffRenderer) handleText(w io.Writer, node *blackfriday.Node, entering bool) {
+	var (
+		start, end string
+	)
+	// handle special roff table cell text encapsulation
+	if node.Parent.Type == blackfriday.TableCell {
+		if len(node.Literal) > 30 {
+			start = tableCellStart
+			end = tableCellEnd
+		} else {
+			// end rows that aren't terminated by "tableCellEnd" with a cr if end of row
+			if node.Parent.Next == nil && !node.Parent.IsHeader {
+				end = crTag
+			}
+		}
+	}
+	out(w, start)
+	escapeSpecialChars(w, node.Literal)
+	out(w, end)
+}
+
+func (r *roffRenderer) handleHeading(w io.Writer, node *blackfriday.Node, entering bool) {
+	if entering {
+		switch node.Level {
+		case 1:
+			if !r.firstHeader {
+				out(w, titleHeader)
+				r.firstHeader = true
+				break
+			}
+			out(w, topLevelHeader)
+		case 2:
+			out(w, secondLevelHdr)
+		default:
+			out(w, otherHeader)
+		}
+	}
+}
+
+func (r *roffRenderer) handleList(w io.Writer, node *blackfriday.Node, entering bool) {
+	openTag := listTag
+	closeTag := listCloseTag
+	if node.ListFlags&blackfriday.ListTypeDefinition != 0 {
+		// tags for definition lists handled within Item node
+		openTag = ""
+		closeTag = ""
+	}
+	if entering {
+		r.listDepth++
+		if node.ListFlags&blackfriday.ListTypeOrdered != 0 {
+			r.listCounters = append(r.listCounters, 1)
+		}
+		out(w, openTag)
+	} else {
+		if node.ListFlags&blackfriday.ListTypeOrdered != 0 {
+			r.listCounters = r.listCounters[:len(r.listCounters)-1]
+		}
+		out(w, closeTag)
+		r.listDepth--
+	}
+}
+
+func (r *roffRenderer) handleItem(w io.Writer, node *blackfriday.Node, entering bool) {
+	if entering {
+		if node.ListFlags&blackfriday.ListTypeOrdered != 0 {
+			out(w, fmt.Sprintf(".IP \"%3d.\" 5\n", r.listCounters[len(r.listCounters)-1]))
+			r.listCounters[len(r.listCounters)-1]++
+		} else if node.ListFlags&blackfriday.ListTypeDefinition != 0 {
+			// state machine for handling terms and following definitions
+			// since blackfriday does not distinguish them properly, nor
+			// does it seperate them into separate lists as it should
+			if !r.defineTerm {
+				out(w, arglistTag)
+				r.defineTerm = true
+			} else {
+				r.defineTerm = false
+			}
+		} else {
+			out(w, ".IP \\(bu 2\n")
+		}
+	} else {
+		out(w, "\n")
+	}
+}
+
+func (r *roffRenderer) handleTable(w io.Writer, node *blackfriday.Node, entering bool) {
+	if entering {
+		out(w, tableStart)
+		//call walker to count cells (and rows?) so format section can be produced
+		columns := countColumns(node)
+		out(w, strings.Repeat("l ", columns)+"\n")
+		out(w, strings.Repeat("l ", columns)+".\n")
+	} else {
+		out(w, tableEnd)
+	}
+}
+
+func (r *roffRenderer) handleTableCell(w io.Writer, node *blackfriday.Node, entering bool) {
+	var (
+		start, end string
+	)
+	if node.IsHeader {
+		start = codespanTag
+		end = codespanCloseTag
+	}
+	if entering {
+		if node.Prev != nil && node.Prev.Type == blackfriday.TableCell {
+			out(w, "\t"+start)
+		} else {
+			out(w, start)
+		}
+	} else {
+		// need to carriage return if we are at the end of the header row
+		if node.IsHeader && node.Next == nil {
+			end = end + crTag
+		}
+		out(w, end)
+	}
+}
+
+// because roff format requires knowing the column count before outputting any table
+// data we need to walk a table tree and count the columns
+func countColumns(node *blackfriday.Node) int {
+	var columns int
+
+	node.Walk(func(node *blackfriday.Node, entering bool) blackfriday.WalkStatus {
+		switch node.Type {
+		case blackfriday.TableRow:
+			if !entering {
+				return blackfriday.Terminate
+			}
+		case blackfriday.TableCell:
+			if entering {
+				columns++
+			}
+		default:
+		}
+		return blackfriday.GoToNext
+	})
+	return columns
+}
+
+func out(w io.Writer, output string) {
+	io.WriteString(w, output) // nolint: errcheck
+}
+
+func needsBackslash(c byte) bool {
+	for _, r := range []byte("-_&\\~") {
+		if c == r {
+			return true
+		}
+	}
+	return false
+}
+
+func escapeSpecialChars(w io.Writer, text []byte) {
+	for i := 0; i < len(text); i++ {
+		// escape initial apostrophe or period
+		if len(text) >= 1 && (text[0] == '\'' || text[0] == '.') {
+			out(w, "\\&")
+		}
+
+		// directly copy normal characters
+		org := i
+
+		for i < len(text) && !needsBackslash(text[i]) {
+			i++
+		}
+		if i > org {
+			w.Write(text[org:i]) // nolint: errcheck
+		}
+
+		// escape a character
+		if i >= len(text) {
+			break
+		}
+
+		w.Write([]byte{'\\', text[i]}) // nolint: errcheck
+	}
+}
diff --git a/vendor/github.com/russross/blackfriday/html.go b/vendor/github.com/russross/blackfriday/html.go
deleted file mode 100644
index 74e67ee82b..0000000000
--- a/vendor/github.com/russross/blackfriday/html.go
+++ /dev/null
@@ -1,949 +0,0 @@
-//
-// Blackfriday Markdown Processor
-// Available at http://github.com/russross/blackfriday
-//
-// Copyright © 2011 Russ Ross <russ@russross.com>.
-// Distributed under the Simplified BSD License.
-// See README.md for details.
-//
-
-//
-//
-// HTML rendering backend
-//
-//
-
-package blackfriday
-
-import (
-	"bytes"
-	"fmt"
-	"regexp"
-	"strconv"
-	"strings"
-)
-
-// Html renderer configuration options.
-const (
-	HTML_SKIP_HTML                 = 1 << iota // skip preformatted HTML blocks
-	HTML_SKIP_STYLE                            // skip embedded <style> elements
-	HTML_SKIP_IMAGES                           // skip embedded images
-	HTML_SKIP_LINKS                            // skip all links
-	HTML_SAFELINK                              // only link to trusted protocols
-	HTML_NOFOLLOW_LINKS                        // only link with rel="nofollow"
-	HTML_NOREFERRER_LINKS                      // only link with rel="noreferrer"
-	HTML_HREF_TARGET_BLANK                     // add a blank target
-	HTML_TOC                                   // generate a table of contents
-	HTML_OMIT_CONTENTS                         // skip the main contents (for a standalone table of contents)
-	HTML_COMPLETE_PAGE                         // generate a complete HTML page
-	HTML_USE_XHTML                             // generate XHTML output instead of HTML
-	HTML_USE_SMARTYPANTS                       // enable smart punctuation substitutions
-	HTML_SMARTYPANTS_FRACTIONS                 // enable smart fractions (with HTML_USE_SMARTYPANTS)
-	HTML_SMARTYPANTS_DASHES                    // enable smart dashes (with HTML_USE_SMARTYPANTS)
-	HTML_SMARTYPANTS_LATEX_DASHES              // enable LaTeX-style dashes (with HTML_USE_SMARTYPANTS and HTML_SMARTYPANTS_DASHES)
-	HTML_SMARTYPANTS_ANGLED_QUOTES             // enable angled double quotes (with HTML_USE_SMARTYPANTS) for double quotes rendering
-	HTML_FOOTNOTE_RETURN_LINKS                 // generate a link at the end of a footnote to return to the source
-)
-
-var (
-	alignments = []string{
-		"left",
-		"right",
-		"center",
-	}
-
-	// TODO: improve this regexp to catch all possible entities:
-	htmlEntity = regexp.MustCompile(`&[a-z]{2,5};`)
-)
-
-type HtmlRendererParameters struct {
-	// Prepend this text to each relative URL.
-	AbsolutePrefix string
-	// Add this text to each footnote anchor, to ensure uniqueness.
-	FootnoteAnchorPrefix string
-	// Show this text inside the <a> tag for a footnote return link, if the
-	// HTML_FOOTNOTE_RETURN_LINKS flag is enabled. If blank, the string
-	// <sup>[return]</sup> is used.
-	FootnoteReturnLinkContents string
-	// If set, add this text to the front of each Header ID, to ensure
-	// uniqueness.
-	HeaderIDPrefix string
-	// If set, add this text to the back of each Header ID, to ensure uniqueness.
-	HeaderIDSuffix string
-}
-
-// Html is a type that implements the Renderer interface for HTML output.
-//
-// Do not create this directly, instead use the HtmlRenderer function.
-type Html struct {
-	flags    int    // HTML_* options
-	closeTag string // how to end singleton tags: either " />" or ">"
-	title    string // document title
-	css      string // optional css file url (used with HTML_COMPLETE_PAGE)
-
-	parameters HtmlRendererParameters
-
-	// table of contents data
-	tocMarker    int
-	headerCount  int
-	currentLevel int
-	toc          *bytes.Buffer
-
-	// Track header IDs to prevent ID collision in a single generation.
-	headerIDs map[string]int
-
-	smartypants *smartypantsRenderer
-}
-
-const (
-	xhtmlClose = " />"
-	htmlClose  = ">"
-)
-
-// HtmlRenderer creates and configures an Html object, which
-// satisfies the Renderer interface.
-//
-// flags is a set of HTML_* options ORed together.
-// title is the title of the document, and css is a URL for the document's
-// stylesheet.
-// title and css are only used when HTML_COMPLETE_PAGE is selected.
-func HtmlRenderer(flags int, title string, css string) Renderer {
-	return HtmlRendererWithParameters(flags, title, css, HtmlRendererParameters{})
-}
-
-func HtmlRendererWithParameters(flags int, title string,
-	css string, renderParameters HtmlRendererParameters) Renderer {
-	// configure the rendering engine
-	closeTag := htmlClose
-	if flags&HTML_USE_XHTML != 0 {
-		closeTag = xhtmlClose
-	}
-
-	if renderParameters.FootnoteReturnLinkContents == "" {
-		renderParameters.FootnoteReturnLinkContents = `<sup>[return]</sup>`
-	}
-
-	return &Html{
-		flags:      flags,
-		closeTag:   closeTag,
-		title:      title,
-		css:        css,
-		parameters: renderParameters,
-
-		headerCount:  0,
-		currentLevel: 0,
-		toc:          new(bytes.Buffer),
-
-		headerIDs: make(map[string]int),
-
-		smartypants: smartypants(flags),
-	}
-}
-
-// Using if statements is a bit faster than a switch statement. As the compiler
-// improves, this should be unnecessary this is only worthwhile because
-// attrEscape is the single largest CPU user in normal use.
-// Also tried using map, but that gave a ~3x slowdown.
-func escapeSingleChar(char byte) (string, bool) {
-	if char == '"' {
-		return "&quot;", true
-	}
-	if char == '&' {
-		return "&amp;", true
-	}
-	if char == '<' {
-		return "&lt;", true
-	}
-	if char == '>' {
-		return "&gt;", true
-	}
-	return "", false
-}
-
-func attrEscape(out *bytes.Buffer, src []byte) {
-	org := 0
-	for i, ch := range src {
-		if entity, ok := escapeSingleChar(ch); ok {
-			if i > org {
-				// copy all the normal characters since the last escape
-				out.Write(src[org:i])
-			}
-			org = i + 1
-			out.WriteString(entity)
-		}
-	}
-	if org < len(src) {
-		out.Write(src[org:])
-	}
-}
-
-func entityEscapeWithSkip(out *bytes.Buffer, src []byte, skipRanges [][]int) {
-	end := 0
-	for _, rang := range skipRanges {
-		attrEscape(out, src[end:rang[0]])
-		out.Write(src[rang[0]:rang[1]])
-		end = rang[1]
-	}
-	attrEscape(out, src[end:])
-}
-
-func (options *Html) GetFlags() int {
-	return options.flags
-}
-
-func (options *Html) TitleBlock(out *bytes.Buffer, text []byte) {
-	text = bytes.TrimPrefix(text, []byte("% "))
-	text = bytes.Replace(text, []byte("\n% "), []byte("\n"), -1)
-	out.WriteString("<h1 class=\"title\">")
-	out.Write(text)
-	out.WriteString("\n</h1>")
-}
-
-func (options *Html) Header(out *bytes.Buffer, text func() bool, level int, id string) {
-	marker := out.Len()
-	doubleSpace(out)
-
-	if id == "" && options.flags&HTML_TOC != 0 {
-		id = fmt.Sprintf("toc_%d", options.headerCount)
-	}
-
-	if id != "" {
-		id = options.ensureUniqueHeaderID(id)
-
-		if options.parameters.HeaderIDPrefix != "" {
-			id = options.parameters.HeaderIDPrefix + id
-		}
-
-		if options.parameters.HeaderIDSuffix != "" {
-			id = id + options.parameters.HeaderIDSuffix
-		}
-
-		out.WriteString(fmt.Sprintf("<h%d id=\"%s\">", level, id))
-	} else {
-		out.WriteString(fmt.Sprintf("<h%d>", level))
-	}
-
-	tocMarker := out.Len()
-	if !text() {
-		out.Truncate(marker)
-		return
-	}
-
-	// are we building a table of contents?
-	if options.flags&HTML_TOC != 0 {
-		options.TocHeaderWithAnchor(out.Bytes()[tocMarker:], level, id)
-	}
-
-	out.WriteString(fmt.Sprintf("</h%d>\n", level))
-}
-
-func (options *Html) BlockHtml(out *bytes.Buffer, text []byte) {
-	if options.flags&HTML_SKIP_HTML != 0 {
-		return
-	}
-
-	doubleSpace(out)
-	out.Write(text)
-	out.WriteByte('\n')
-}
-
-func (options *Html) HRule(out *bytes.Buffer) {
-	doubleSpace(out)
-	out.WriteString("<hr")
-	out.WriteString(options.closeTag)
-	out.WriteByte('\n')
-}
-
-func (options *Html) BlockCode(out *bytes.Buffer, text []byte, lang string) {
-	doubleSpace(out)
-
-	// parse out the language names/classes
-	count := 0
-	for _, elt := range strings.Fields(lang) {
-		if elt[0] == '.' {
-			elt = elt[1:]
-		}
-		if len(elt) == 0 {
-			continue
-		}
-		if count == 0 {
-			out.WriteString("<pre><code class=\"language-")
-		} else {
-			out.WriteByte(' ')
-		}
-		attrEscape(out, []byte(elt))
-		count++
-	}
-
-	if count == 0 {
-		out.WriteString("<pre><code>")
-	} else {
-		out.WriteString("\">")
-	}
-
-	attrEscape(out, text)
-	out.WriteString("</code></pre>\n")
-}
-
-func (options *Html) BlockQuote(out *bytes.Buffer, text []byte) {
-	doubleSpace(out)
-	out.WriteString("<blockquote>\n")
-	out.Write(text)
-	out.WriteString("</blockquote>\n")
-}
-
-func (options *Html) Table(out *bytes.Buffer, header []byte, body []byte, columnData []int) {
-	doubleSpace(out)
-	out.WriteString("<table>\n<thead>\n")
-	out.Write(header)
-	out.WriteString("</thead>\n\n<tbody>\n")
-	out.Write(body)
-	out.WriteString("</tbody>\n</table>\n")
-}
-
-func (options *Html) TableRow(out *bytes.Buffer, text []byte) {
-	doubleSpace(out)
-	out.WriteString("<tr>\n")
-	out.Write(text)
-	out.WriteString("\n</tr>\n")
-}
-
-func (options *Html) TableHeaderCell(out *bytes.Buffer, text []byte, align int) {
-	doubleSpace(out)
-	switch align {
-	case TABLE_ALIGNMENT_LEFT:
-		out.WriteString("<th align=\"left\">")
-	case TABLE_ALIGNMENT_RIGHT:
-		out.WriteString("<th align=\"right\">")
-	case TABLE_ALIGNMENT_CENTER:
-		out.WriteString("<th align=\"center\">")
-	default:
-		out.WriteString("<th>")
-	}
-
-	out.Write(text)
-	out.WriteString("</th>")
-}
-
-func (options *Html) TableCell(out *bytes.Buffer, text []byte, align int) {
-	doubleSpace(out)
-	switch align {
-	case TABLE_ALIGNMENT_LEFT:
-		out.WriteString("<td align=\"left\">")
-	case TABLE_ALIGNMENT_RIGHT:
-		out.WriteString("<td align=\"right\">")
-	case TABLE_ALIGNMENT_CENTER:
-		out.WriteString("<td align=\"center\">")
-	default:
-		out.WriteString("<td>")
-	}
-
-	out.Write(text)
-	out.WriteString("</td>")
-}
-
-func (options *Html) Footnotes(out *bytes.Buffer, text func() bool) {
-	out.WriteString("<div class=\"footnotes\">\n")
-	options.HRule(out)
-	options.List(out, text, LIST_TYPE_ORDERED)
-	out.WriteString("</div>\n")
-}
-
-func (options *Html) FootnoteItem(out *bytes.Buffer, name, text []byte, flags int) {
-	if flags&LIST_ITEM_CONTAINS_BLOCK != 0 || flags&LIST_ITEM_BEGINNING_OF_LIST != 0 {
-		doubleSpace(out)
-	}
-	slug := slugify(name)
-	out.WriteString(`<li id="`)
-	out.WriteString(`fn:`)
-	out.WriteString(options.parameters.FootnoteAnchorPrefix)
-	out.Write(slug)
-	out.WriteString(`">`)
-	out.Write(text)
-	if options.flags&HTML_FOOTNOTE_RETURN_LINKS != 0 {
-		out.WriteString(` <a class="footnote-return" href="#`)
-		out.WriteString(`fnref:`)
-		out.WriteString(options.parameters.FootnoteAnchorPrefix)
-		out.Write(slug)
-		out.WriteString(`">`)
-		out.WriteString(options.parameters.FootnoteReturnLinkContents)
-		out.WriteString(`</a>`)
-	}
-	out.WriteString("</li>\n")
-}
-
-func (options *Html) List(out *bytes.Buffer, text func() bool, flags int) {
-	marker := out.Len()
-	doubleSpace(out)
-
-	if flags&LIST_TYPE_DEFINITION != 0 {
-		out.WriteString("<dl>")
-	} else if flags&LIST_TYPE_ORDERED != 0 {
-		out.WriteString("<ol>")
-	} else {
-		out.WriteString("<ul>")
-	}
-	if !text() {
-		out.Truncate(marker)
-		return
-	}
-	if flags&LIST_TYPE_DEFINITION != 0 {
-		out.WriteString("</dl>\n")
-	} else if flags&LIST_TYPE_ORDERED != 0 {
-		out.WriteString("</ol>\n")
-	} else {
-		out.WriteString("</ul>\n")
-	}
-}
-
-func (options *Html) ListItem(out *bytes.Buffer, text []byte, flags int) {
-	if (flags&LIST_ITEM_CONTAINS_BLOCK != 0 && flags&LIST_TYPE_DEFINITION == 0) ||
-		flags&LIST_ITEM_BEGINNING_OF_LIST != 0 {
-		doubleSpace(out)
-	}
-	if flags&LIST_TYPE_TERM != 0 {
-		out.WriteString("<dt>")
-	} else if flags&LIST_TYPE_DEFINITION != 0 {
-		out.WriteString("<dd>")
-	} else {
-		out.WriteString("<li>")
-	}
-	out.Write(text)
-	if flags&LIST_TYPE_TERM != 0 {
-		out.WriteString("</dt>\n")
-	} else if flags&LIST_TYPE_DEFINITION != 0 {
-		out.WriteString("</dd>\n")
-	} else {
-		out.WriteString("</li>\n")
-	}
-}
-
-func (options *Html) Paragraph(out *bytes.Buffer, text func() bool) {
-	marker := out.Len()
-	doubleSpace(out)
-
-	out.WriteString("<p>")
-	if !text() {
-		out.Truncate(marker)
-		return
-	}
-	out.WriteString("</p>\n")
-}
-
-func (options *Html) AutoLink(out *bytes.Buffer, link []byte, kind int) {
-	skipRanges := htmlEntity.FindAllIndex(link, -1)
-	if options.flags&HTML_SAFELINK != 0 && !isSafeLink(link) && kind != LINK_TYPE_EMAIL {
-		// mark it but don't link it if it is not a safe link: no smartypants
-		out.WriteString("<tt>")
-		entityEscapeWithSkip(out, link, skipRanges)
-		out.WriteString("</tt>")
-		return
-	}
-
-	out.WriteString("<a href=\"")
-	if kind == LINK_TYPE_EMAIL {
-		out.WriteString("mailto:")
-	} else {
-		options.maybeWriteAbsolutePrefix(out, link)
-	}
-
-	entityEscapeWithSkip(out, link, skipRanges)
-
-	var relAttrs []string
-	if options.flags&HTML_NOFOLLOW_LINKS != 0 && !isRelativeLink(link) {
-		relAttrs = append(relAttrs, "nofollow")
-	}
-	if options.flags&HTML_NOREFERRER_LINKS != 0 && !isRelativeLink(link) {
-		relAttrs = append(relAttrs, "noreferrer")
-	}
-	if len(relAttrs) > 0 {
-		out.WriteString(fmt.Sprintf("\" rel=\"%s", strings.Join(relAttrs, " ")))
-	}
-
-	// blank target only add to external link
-	if options.flags&HTML_HREF_TARGET_BLANK != 0 && !isRelativeLink(link) {
-		out.WriteString("\" target=\"_blank")
-	}
-
-	out.WriteString("\">")
-
-	// Pretty print: if we get an email address as
-	// an actual URI, e.g. `mailto:foo@bar.com`, we don't
-	// want to print the `mailto:` prefix
-	switch {
-	case bytes.HasPrefix(link, []byte("mailto://")):
-		attrEscape(out, link[len("mailto://"):])
-	case bytes.HasPrefix(link, []byte("mailto:")):
-		attrEscape(out, link[len("mailto:"):])
-	default:
-		entityEscapeWithSkip(out, link, skipRanges)
-	}
-
-	out.WriteString("</a>")
-}
-
-func (options *Html) CodeSpan(out *bytes.Buffer, text []byte) {
-	out.WriteString("<code>")
-	attrEscape(out, text)
-	out.WriteString("</code>")
-}
-
-func (options *Html) DoubleEmphasis(out *bytes.Buffer, text []byte) {
-	out.WriteString("<strong>")
-	out.Write(text)
-	out.WriteString("</strong>")
-}
-
-func (options *Html) Emphasis(out *bytes.Buffer, text []byte) {
-	if len(text) == 0 {
-		return
-	}
-	out.WriteString("<em>")
-	out.Write(text)
-	out.WriteString("</em>")
-}
-
-func (options *Html) maybeWriteAbsolutePrefix(out *bytes.Buffer, link []byte) {
-	if options.parameters.AbsolutePrefix != "" && isRelativeLink(link) && link[0] != '.' {
-		out.WriteString(options.parameters.AbsolutePrefix)
-		if link[0] != '/' {
-			out.WriteByte('/')
-		}
-	}
-}
-
-func (options *Html) Image(out *bytes.Buffer, link []byte, title []byte, alt []byte) {
-	if options.flags&HTML_SKIP_IMAGES != 0 {
-		return
-	}
-
-	out.WriteString("<img src=\"")
-	options.maybeWriteAbsolutePrefix(out, link)
-	attrEscape(out, link)
-	out.WriteString("\" alt=\"")
-	if len(alt) > 0 {
-		attrEscape(out, alt)
-	}
-	if len(title) > 0 {
-		out.WriteString("\" title=\"")
-		attrEscape(out, title)
-	}
-
-	out.WriteByte('"')
-	out.WriteString(options.closeTag)
-}
-
-func (options *Html) LineBreak(out *bytes.Buffer) {
-	out.WriteString("<br")
-	out.WriteString(options.closeTag)
-	out.WriteByte('\n')
-}
-
-func (options *Html) Link(out *bytes.Buffer, link []byte, title []byte, content []byte) {
-	if options.flags&HTML_SKIP_LINKS != 0 {
-		// write the link text out but don't link it, just mark it with typewriter font
-		out.WriteString("<tt>")
-		attrEscape(out, content)
-		out.WriteString("</tt>")
-		return
-	}
-
-	if options.flags&HTML_SAFELINK != 0 && !isSafeLink(link) {
-		// write the link text out but don't link it, just mark it with typewriter font
-		out.WriteString("<tt>")
-		attrEscape(out, content)
-		out.WriteString("</tt>")
-		return
-	}
-
-	out.WriteString("<a href=\"")
-	options.maybeWriteAbsolutePrefix(out, link)
-	attrEscape(out, link)
-	if len(title) > 0 {
-		out.WriteString("\" title=\"")
-		attrEscape(out, title)
-	}
-	var relAttrs []string
-	if options.flags&HTML_NOFOLLOW_LINKS != 0 && !isRelativeLink(link) {
-		relAttrs = append(relAttrs, "nofollow")
-	}
-	if options.flags&HTML_NOREFERRER_LINKS != 0 && !isRelativeLink(link) {
-		relAttrs = append(relAttrs, "noreferrer")
-	}
-	if len(relAttrs) > 0 {
-		out.WriteString(fmt.Sprintf("\" rel=\"%s", strings.Join(relAttrs, " ")))
-	}
-
-	// blank target only add to external link
-	if options.flags&HTML_HREF_TARGET_BLANK != 0 && !isRelativeLink(link) {
-		out.WriteString("\" target=\"_blank")
-	}
-
-	out.WriteString("\">")
-	out.Write(content)
-	out.WriteString("</a>")
-	return
-}
-
-func (options *Html) RawHtmlTag(out *bytes.Buffer, text []byte) {
-	if options.flags&HTML_SKIP_HTML != 0 {
-		return
-	}
-	if options.flags&HTML_SKIP_STYLE != 0 && isHtmlTag(text, "style") {
-		return
-	}
-	if options.flags&HTML_SKIP_LINKS != 0 && isHtmlTag(text, "a") {
-		return
-	}
-	if options.flags&HTML_SKIP_IMAGES != 0 && isHtmlTag(text, "img") {
-		return
-	}
-	out.Write(text)
-}
-
-func (options *Html) TripleEmphasis(out *bytes.Buffer, text []byte) {
-	out.WriteString("<strong><em>")
-	out.Write(text)
-	out.WriteString("</em></strong>")
-}
-
-func (options *Html) StrikeThrough(out *bytes.Buffer, text []byte) {
-	out.WriteString("<del>")
-	out.Write(text)
-	out.WriteString("</del>")
-}
-
-func (options *Html) FootnoteRef(out *bytes.Buffer, ref []byte, id int) {
-	slug := slugify(ref)
-	out.WriteString(`<sup class="footnote-ref" id="`)
-	out.WriteString(`fnref:`)
-	out.WriteString(options.parameters.FootnoteAnchorPrefix)
-	out.Write(slug)
-	out.WriteString(`"><a rel="footnote" href="#`)
-	out.WriteString(`fn:`)
-	out.WriteString(options.parameters.FootnoteAnchorPrefix)
-	out.Write(slug)
-	out.WriteString(`">`)
-	out.WriteString(strconv.Itoa(id))
-	out.WriteString(`</a></sup>`)
-}
-
-func (options *Html) Entity(out *bytes.Buffer, entity []byte) {
-	out.Write(entity)
-}
-
-func (options *Html) NormalText(out *bytes.Buffer, text []byte) {
-	if options.flags&HTML_USE_SMARTYPANTS != 0 {
-		options.Smartypants(out, text)
-	} else {
-		attrEscape(out, text)
-	}
-}
-
-func (options *Html) Smartypants(out *bytes.Buffer, text []byte) {
-	smrt := smartypantsData{false, false}
-
-	// first do normal entity escaping
-	var escaped bytes.Buffer
-	attrEscape(&escaped, text)
-	text = escaped.Bytes()
-
-	mark := 0
-	for i := 0; i < len(text); i++ {
-		if action := options.smartypants[text[i]]; action != nil {
-			if i > mark {
-				out.Write(text[mark:i])
-			}
-
-			previousChar := byte(0)
-			if i > 0 {
-				previousChar = text[i-1]
-			}
-			i += action(out, &smrt, previousChar, text[i:])
-			mark = i + 1
-		}
-	}
-
-	if mark < len(text) {
-		out.Write(text[mark:])
-	}
-}
-
-func (options *Html) DocumentHeader(out *bytes.Buffer) {
-	if options.flags&HTML_COMPLETE_PAGE == 0 {
-		return
-	}
-
-	ending := ""
-	if options.flags&HTML_USE_XHTML != 0 {
-		out.WriteString("<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\" ")
-		out.WriteString("\"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">\n")
-		out.WriteString("<html xmlns=\"http://www.w3.org/1999/xhtml\">\n")
-		ending = " /"
-	} else {
-		out.WriteString("<!DOCTYPE html>\n")
-		out.WriteString("<html>\n")
-	}
-	out.WriteString("<head>\n")
-	out.WriteString("  <title>")
-	options.NormalText(out, []byte(options.title))
-	out.WriteString("</title>\n")
-	out.WriteString("  <meta name=\"GENERATOR\" content=\"Blackfriday Markdown Processor v")
-	out.WriteString(VERSION)
-	out.WriteString("\"")
-	out.WriteString(ending)
-	out.WriteString(">\n")
-	out.WriteString("  <meta charset=\"utf-8\"")
-	out.WriteString(ending)
-	out.WriteString(">\n")
-	if options.css != "" {
-		out.WriteString("  <link rel=\"stylesheet\" type=\"text/css\" href=\"")
-		attrEscape(out, []byte(options.css))
-		out.WriteString("\"")
-		out.WriteString(ending)
-		out.WriteString(">\n")
-	}
-	out.WriteString("</head>\n")
-	out.WriteString("<body>\n")
-
-	options.tocMarker = out.Len()
-}
-
-func (options *Html) DocumentFooter(out *bytes.Buffer) {
-	// finalize and insert the table of contents
-	if options.flags&HTML_TOC != 0 {
-		options.TocFinalize()
-
-		// now we have to insert the table of contents into the document
-		var temp bytes.Buffer
-
-		// start by making a copy of everything after the document header
-		temp.Write(out.Bytes()[options.tocMarker:])
-
-		// now clear the copied material from the main output buffer
-		out.Truncate(options.tocMarker)
-
-		// corner case spacing issue
-		if options.flags&HTML_COMPLETE_PAGE != 0 {
-			out.WriteByte('\n')
-		}
-
-		// insert the table of contents
-		out.WriteString("<nav>\n")
-		out.Write(options.toc.Bytes())
-		out.WriteString("</nav>\n")
-
-		// corner case spacing issue
-		if options.flags&HTML_COMPLETE_PAGE == 0 && options.flags&HTML_OMIT_CONTENTS == 0 {
-			out.WriteByte('\n')
-		}
-
-		// write out everything that came after it
-		if options.flags&HTML_OMIT_CONTENTS == 0 {
-			out.Write(temp.Bytes())
-		}
-	}
-
-	if options.flags&HTML_COMPLETE_PAGE != 0 {
-		out.WriteString("\n</body>\n")
-		out.WriteString("</html>\n")
-	}
-
-}
-
-func (options *Html) TocHeaderWithAnchor(text []byte, level int, anchor string) {
-	for level > options.currentLevel {
-		switch {
-		case bytes.HasSuffix(options.toc.Bytes(), []byte("</li>\n")):
-			// this sublist can nest underneath a header
-			size := options.toc.Len()
-			options.toc.Truncate(size - len("</li>\n"))
-
-		case options.currentLevel > 0:
-			options.toc.WriteString("<li>")
-		}
-		if options.toc.Len() > 0 {
-			options.toc.WriteByte('\n')
-		}
-		options.toc.WriteString("<ul>\n")
-		options.currentLevel++
-	}
-
-	for level < options.currentLevel {
-		options.toc.WriteString("</ul>")
-		if options.currentLevel > 1 {
-			options.toc.WriteString("</li>\n")
-		}
-		options.currentLevel--
-	}
-
-	options.toc.WriteString("<li><a href=\"#")
-	if anchor != "" {
-		options.toc.WriteString(anchor)
-	} else {
-		options.toc.WriteString("toc_")
-		options.toc.WriteString(strconv.Itoa(options.headerCount))
-	}
-	options.toc.WriteString("\">")
-	options.headerCount++
-
-	options.toc.Write(text)
-
-	options.toc.WriteString("</a></li>\n")
-}
-
-func (options *Html) TocHeader(text []byte, level int) {
-	options.TocHeaderWithAnchor(text, level, "")
-}
-
-func (options *Html) TocFinalize() {
-	for options.currentLevel > 1 {
-		options.toc.WriteString("</ul></li>\n")
-		options.currentLevel--
-	}
-
-	if options.currentLevel > 0 {
-		options.toc.WriteString("</ul>\n")
-	}
-}
-
-func isHtmlTag(tag []byte, tagname string) bool {
-	found, _ := findHtmlTagPos(tag, tagname)
-	return found
-}
-
-// Look for a character, but ignore it when it's in any kind of quotes, it
-// might be JavaScript
-func skipUntilCharIgnoreQuotes(html []byte, start int, char byte) int {
-	inSingleQuote := false
-	inDoubleQuote := false
-	inGraveQuote := false
-	i := start
-	for i < len(html) {
-		switch {
-		case html[i] == char && !inSingleQuote && !inDoubleQuote && !inGraveQuote:
-			return i
-		case html[i] == '\'':
-			inSingleQuote = !inSingleQuote
-		case html[i] == '"':
-			inDoubleQuote = !inDoubleQuote
-		case html[i] == '`':
-			inGraveQuote = !inGraveQuote
-		}
-		i++
-	}
-	return start
-}
-
-func findHtmlTagPos(tag []byte, tagname string) (bool, int) {
-	i := 0
-	if i < len(tag) && tag[0] != '<' {
-		return false, -1
-	}
-	i++
-	i = skipSpace(tag, i)
-
-	if i < len(tag) && tag[i] == '/' {
-		i++
-	}
-
-	i = skipSpace(tag, i)
-	j := 0
-	for ; i < len(tag); i, j = i+1, j+1 {
-		if j >= len(tagname) {
-			break
-		}
-
-		if strings.ToLower(string(tag[i]))[0] != tagname[j] {
-			return false, -1
-		}
-	}
-
-	if i == len(tag) {
-		return false, -1
-	}
-
-	rightAngle := skipUntilCharIgnoreQuotes(tag, i, '>')
-	if rightAngle > i {
-		return true, rightAngle
-	}
-
-	return false, -1
-}
-
-func skipUntilChar(text []byte, start int, char byte) int {
-	i := start
-	for i < len(text) && text[i] != char {
-		i++
-	}
-	return i
-}
-
-func skipSpace(tag []byte, i int) int {
-	for i < len(tag) && isspace(tag[i]) {
-		i++
-	}
-	return i
-}
-
-func skipChar(data []byte, start int, char byte) int {
-	i := start
-	for i < len(data) && data[i] == char {
-		i++
-	}
-	return i
-}
-
-func doubleSpace(out *bytes.Buffer) {
-	if out.Len() > 0 {
-		out.WriteByte('\n')
-	}
-}
-
-func isRelativeLink(link []byte) (yes bool) {
-	// a tag begin with '#'
-	if link[0] == '#' {
-		return true
-	}
-
-	// link begin with '/' but not '//', the second maybe a protocol relative link
-	if len(link) >= 2 && link[0] == '/' && link[1] != '/' {
-		return true
-	}
-
-	// only the root '/'
-	if len(link) == 1 && link[0] == '/' {
-		return true
-	}
-
-	// current directory : begin with "./"
-	if bytes.HasPrefix(link, []byte("./")) {
-		return true
-	}
-
-	// parent directory : begin with "../"
-	if bytes.HasPrefix(link, []byte("../")) {
-		return true
-	}
-
-	return false
-}
-
-func (options *Html) ensureUniqueHeaderID(id string) string {
-	for count, found := options.headerIDs[id]; found; count, found = options.headerIDs[id] {
-		tmp := fmt.Sprintf("%s-%d", id, count+1)
-
-		if _, tmpFound := options.headerIDs[tmp]; !tmpFound {
-			options.headerIDs[id] = count + 1
-			id = tmp
-		} else {
-			id = id + "-1"
-		}
-	}
-
-	if _, found := options.headerIDs[id]; !found {
-		options.headerIDs[id] = 0
-	}
-
-	return id
-}
diff --git a/vendor/github.com/russross/blackfriday/latex.go b/vendor/github.com/russross/blackfriday/latex.go
deleted file mode 100644
index 70705aa9c1..0000000000
--- a/vendor/github.com/russross/blackfriday/latex.go
+++ /dev/null
@@ -1,332 +0,0 @@
-//
-// Blackfriday Markdown Processor
-// Available at http://github.com/russross/blackfriday
-//
-// Copyright © 2011 Russ Ross <russ@russross.com>.
-// Distributed under the Simplified BSD License.
-// See README.md for details.
-//
-
-//
-//
-// LaTeX rendering backend
-//
-//
-
-package blackfriday
-
-import (
-	"bytes"
-)
-
-// Latex is a type that implements the Renderer interface for LaTeX output.
-//
-// Do not create this directly, instead use the LatexRenderer function.
-type Latex struct {
-}
-
-// LatexRenderer creates and configures a Latex object, which
-// satisfies the Renderer interface.
-//
-// flags is a set of LATEX_* options ORed together (currently no such options
-// are defined).
-func LatexRenderer(flags int) Renderer {
-	return &Latex{}
-}
-
-func (options *Latex) GetFlags() int {
-	return 0
-}
-
-// render code chunks using verbatim, or listings if we have a language
-func (options *Latex) BlockCode(out *bytes.Buffer, text []byte, lang string) {
-	if lang == "" {
-		out.WriteString("\n\\begin{verbatim}\n")
-	} else {
-		out.WriteString("\n\\begin{lstlisting}[language=")
-		out.WriteString(lang)
-		out.WriteString("]\n")
-	}
-	out.Write(text)
-	if lang == "" {
-		out.WriteString("\n\\end{verbatim}\n")
-	} else {
-		out.WriteString("\n\\end{lstlisting}\n")
-	}
-}
-
-func (options *Latex) TitleBlock(out *bytes.Buffer, text []byte) {
-
-}
-
-func (options *Latex) BlockQuote(out *bytes.Buffer, text []byte) {
-	out.WriteString("\n\\begin{quotation}\n")
-	out.Write(text)
-	out.WriteString("\n\\end{quotation}\n")
-}
-
-func (options *Latex) BlockHtml(out *bytes.Buffer, text []byte) {
-	// a pretty lame thing to do...
-	out.WriteString("\n\\begin{verbatim}\n")
-	out.Write(text)
-	out.WriteString("\n\\end{verbatim}\n")
-}
-
-func (options *Latex) Header(out *bytes.Buffer, text func() bool, level int, id string) {
-	marker := out.Len()
-
-	switch level {
-	case 1:
-		out.WriteString("\n\\section{")
-	case 2:
-		out.WriteString("\n\\subsection{")
-	case 3:
-		out.WriteString("\n\\subsubsection{")
-	case 4:
-		out.WriteString("\n\\paragraph{")
-	case 5:
-		out.WriteString("\n\\subparagraph{")
-	case 6:
-		out.WriteString("\n\\textbf{")
-	}
-	if !text() {
-		out.Truncate(marker)
-		return
-	}
-	out.WriteString("}\n")
-}
-
-func (options *Latex) HRule(out *bytes.Buffer) {
-	out.WriteString("\n\\HRule\n")
-}
-
-func (options *Latex) List(out *bytes.Buffer, text func() bool, flags int) {
-	marker := out.Len()
-	if flags&LIST_TYPE_ORDERED != 0 {
-		out.WriteString("\n\\begin{enumerate}\n")
-	} else {
-		out.WriteString("\n\\begin{itemize}\n")
-	}
-	if !text() {
-		out.Truncate(marker)
-		return
-	}
-	if flags&LIST_TYPE_ORDERED != 0 {
-		out.WriteString("\n\\end{enumerate}\n")
-	} else {
-		out.WriteString("\n\\end{itemize}\n")
-	}
-}
-
-func (options *Latex) ListItem(out *bytes.Buffer, text []byte, flags int) {
-	out.WriteString("\n\\item ")
-	out.Write(text)
-}
-
-func (options *Latex) Paragraph(out *bytes.Buffer, text func() bool) {
-	marker := out.Len()
-	out.WriteString("\n")
-	if !text() {
-		out.Truncate(marker)
-		return
-	}
-	out.WriteString("\n")
-}
-
-func (options *Latex) Table(out *bytes.Buffer, header []byte, body []byte, columnData []int) {
-	out.WriteString("\n\\begin{tabular}{")
-	for _, elt := range columnData {
-		switch elt {
-		case TABLE_ALIGNMENT_LEFT:
-			out.WriteByte('l')
-		case TABLE_ALIGNMENT_RIGHT:
-			out.WriteByte('r')
-		default:
-			out.WriteByte('c')
-		}
-	}
-	out.WriteString("}\n")
-	out.Write(header)
-	out.WriteString(" \\\\\n\\hline\n")
-	out.Write(body)
-	out.WriteString("\n\\end{tabular}\n")
-}
-
-func (options *Latex) TableRow(out *bytes.Buffer, text []byte) {
-	if out.Len() > 0 {
-		out.WriteString(" \\\\\n")
-	}
-	out.Write(text)
-}
-
-func (options *Latex) TableHeaderCell(out *bytes.Buffer, text []byte, align int) {
-	if out.Len() > 0 {
-		out.WriteString(" & ")
-	}
-	out.Write(text)
-}
-
-func (options *Latex) TableCell(out *bytes.Buffer, text []byte, align int) {
-	if out.Len() > 0 {
-		out.WriteString(" & ")
-	}
-	out.Write(text)
-}
-
-// TODO: this
-func (options *Latex) Footnotes(out *bytes.Buffer, text func() bool) {
-
-}
-
-func (options *Latex) FootnoteItem(out *bytes.Buffer, name, text []byte, flags int) {
-
-}
-
-func (options *Latex) AutoLink(out *bytes.Buffer, link []byte, kind int) {
-	out.WriteString("\\href{")
-	if kind == LINK_TYPE_EMAIL {
-		out.WriteString("mailto:")
-	}
-	out.Write(link)
-	out.WriteString("}{")
-	out.Write(link)
-	out.WriteString("}")
-}
-
-func (options *Latex) CodeSpan(out *bytes.Buffer, text []byte) {
-	out.WriteString("\\texttt{")
-	escapeSpecialChars(out, text)
-	out.WriteString("}")
-}
-
-func (options *Latex) DoubleEmphasis(out *bytes.Buffer, text []byte) {
-	out.WriteString("\\textbf{")
-	out.Write(text)
-	out.WriteString("}")
-}
-
-func (options *Latex) Emphasis(out *bytes.Buffer, text []byte) {
-	out.WriteString("\\textit{")
-	out.Write(text)
-	out.WriteString("}")
-}
-
-func (options *Latex) Image(out *bytes.Buffer, link []byte, title []byte, alt []byte) {
-	if bytes.HasPrefix(link, []byte("http://")) || bytes.HasPrefix(link, []byte("https://")) {
-		// treat it like a link
-		out.WriteString("\\href{")
-		out.Write(link)
-		out.WriteString("}{")
-		out.Write(alt)
-		out.WriteString("}")
-	} else {
-		out.WriteString("\\includegraphics{")
-		out.Write(link)
-		out.WriteString("}")
-	}
-}
-
-func (options *Latex) LineBreak(out *bytes.Buffer) {
-	out.WriteString(" \\\\\n")
-}
-
-func (options *Latex) Link(out *bytes.Buffer, link []byte, title []byte, content []byte) {
-	out.WriteString("\\href{")
-	out.Write(link)
-	out.WriteString("}{")
-	out.Write(content)
-	out.WriteString("}")
-}
-
-func (options *Latex) RawHtmlTag(out *bytes.Buffer, tag []byte) {
-}
-
-func (options *Latex) TripleEmphasis(out *bytes.Buffer, text []byte) {
-	out.WriteString("\\textbf{\\textit{")
-	out.Write(text)
-	out.WriteString("}}")
-}
-
-func (options *Latex) StrikeThrough(out *bytes.Buffer, text []byte) {
-	out.WriteString("\\sout{")
-	out.Write(text)
-	out.WriteString("}")
-}
-
-// TODO: this
-func (options *Latex) FootnoteRef(out *bytes.Buffer, ref []byte, id int) {
-
-}
-
-func needsBackslash(c byte) bool {
-	for _, r := range []byte("_{}%$&\\~#") {
-		if c == r {
-			return true
-		}
-	}
-	return false
-}
-
-func escapeSpecialChars(out *bytes.Buffer, text []byte) {
-	for i := 0; i < len(text); i++ {
-		// directly copy normal characters
-		org := i
-
-		for i < len(text) && !needsBackslash(text[i]) {
-			i++
-		}
-		if i > org {
-			out.Write(text[org:i])
-		}
-
-		// escape a character
-		if i >= len(text) {
-			break
-		}
-		out.WriteByte('\\')
-		out.WriteByte(text[i])
-	}
-}
-
-func (options *Latex) Entity(out *bytes.Buffer, entity []byte) {
-	// TODO: convert this into a unicode character or something
-	out.Write(entity)
-}
-
-func (options *Latex) NormalText(out *bytes.Buffer, text []byte) {
-	escapeSpecialChars(out, text)
-}
-
-// header and footer
-func (options *Latex) DocumentHeader(out *bytes.Buffer) {
-	out.WriteString("\\documentclass{article}\n")
-	out.WriteString("\n")
-	out.WriteString("\\usepackage{graphicx}\n")
-	out.WriteString("\\usepackage{listings}\n")
-	out.WriteString("\\usepackage[margin=1in]{geometry}\n")
-	out.WriteString("\\usepackage[utf8]{inputenc}\n")
-	out.WriteString("\\usepackage{verbatim}\n")
-	out.WriteString("\\usepackage[normalem]{ulem}\n")
-	out.WriteString("\\usepackage{hyperref}\n")
-	out.WriteString("\n")
-	out.WriteString("\\hypersetup{colorlinks,%\n")
-	out.WriteString("  citecolor=black,%\n")
-	out.WriteString("  filecolor=black,%\n")
-	out.WriteString("  linkcolor=black,%\n")
-	out.WriteString("  urlcolor=black,%\n")
-	out.WriteString("  pdfstartview=FitH,%\n")
-	out.WriteString("  breaklinks=true,%\n")
-	out.WriteString("  pdfauthor={Blackfriday Markdown Processor v")
-	out.WriteString(VERSION)
-	out.WriteString("}}\n")
-	out.WriteString("\n")
-	out.WriteString("\\newcommand{\\HRule}{\\rule{\\linewidth}{0.5mm}}\n")
-	out.WriteString("\\addtolength{\\parskip}{0.5\\baselineskip}\n")
-	out.WriteString("\\parindent=0pt\n")
-	out.WriteString("\n")
-	out.WriteString("\\begin{document}\n")
-}
-
-func (options *Latex) DocumentFooter(out *bytes.Buffer) {
-	out.WriteString("\n\\end{document}\n")
-}
diff --git a/vendor/github.com/russross/blackfriday/markdown.go b/vendor/github.com/russross/blackfriday/markdown.go
deleted file mode 100644
index aea997a0ea..0000000000
--- a/vendor/github.com/russross/blackfriday/markdown.go
+++ /dev/null
@@ -1,926 +0,0 @@
-//
-// Blackfriday Markdown Processor
-// Available at http://github.com/russross/blackfriday
-//
-// Copyright © 2011 Russ Ross <russ@russross.com>.
-// Distributed under the Simplified BSD License.
-// See README.md for details.
-//
-
-//
-//
-// Markdown parsing and processing
-//
-//
-
-// Blackfriday markdown processor.
-//
-// Translates plain text with simple formatting rules into HTML or LaTeX.
-package blackfriday
-
-import (
-	"bytes"
-	"fmt"
-	"strings"
-	"unicode/utf8"
-)
-
-const VERSION = "1.5"
-
-// These are the supported markdown parsing extensions.
-// OR these values together to select multiple extensions.
-const (
-	EXTENSION_NO_INTRA_EMPHASIS          = 1 << iota // ignore emphasis markers inside words
-	EXTENSION_TABLES                                 // render tables
-	EXTENSION_FENCED_CODE                            // render fenced code blocks
-	EXTENSION_AUTOLINK                               // detect embedded URLs that are not explicitly marked
-	EXTENSION_STRIKETHROUGH                          // strikethrough text using ~~test~~
-	EXTENSION_LAX_HTML_BLOCKS                        // loosen up HTML block parsing rules
-	EXTENSION_SPACE_HEADERS                          // be strict about prefix header rules
-	EXTENSION_HARD_LINE_BREAK                        // translate newlines into line breaks
-	EXTENSION_TAB_SIZE_EIGHT                         // expand tabs to eight spaces instead of four
-	EXTENSION_FOOTNOTES                              // Pandoc-style footnotes
-	EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK             // No need to insert an empty line to start a (code, quote, ordered list, unordered list) block
-	EXTENSION_HEADER_IDS                             // specify header IDs  with {#id}
-	EXTENSION_TITLEBLOCK                             // Titleblock ala pandoc
-	EXTENSION_AUTO_HEADER_IDS                        // Create the header ID from the text
-	EXTENSION_BACKSLASH_LINE_BREAK                   // translate trailing backslashes into line breaks
-	EXTENSION_DEFINITION_LISTS                       // render definition lists
-
-	commonHtmlFlags = 0 |
-		HTML_USE_XHTML |
-		HTML_USE_SMARTYPANTS |
-		HTML_SMARTYPANTS_FRACTIONS |
-		HTML_SMARTYPANTS_DASHES |
-		HTML_SMARTYPANTS_LATEX_DASHES
-
-	commonExtensions = 0 |
-		EXTENSION_NO_INTRA_EMPHASIS |
-		EXTENSION_TABLES |
-		EXTENSION_FENCED_CODE |
-		EXTENSION_AUTOLINK |
-		EXTENSION_STRIKETHROUGH |
-		EXTENSION_SPACE_HEADERS |
-		EXTENSION_HEADER_IDS |
-		EXTENSION_BACKSLASH_LINE_BREAK |
-		EXTENSION_DEFINITION_LISTS
-)
-
-// These are the possible flag values for the link renderer.
-// Only a single one of these values will be used; they are not ORed together.
-// These are mostly of interest if you are writing a new output format.
-const (
-	LINK_TYPE_NOT_AUTOLINK = iota
-	LINK_TYPE_NORMAL
-	LINK_TYPE_EMAIL
-)
-
-// These are the possible flag values for the ListItem renderer.
-// Multiple flag values may be ORed together.
-// These are mostly of interest if you are writing a new output format.
-const (
-	LIST_TYPE_ORDERED = 1 << iota
-	LIST_TYPE_DEFINITION
-	LIST_TYPE_TERM
-	LIST_ITEM_CONTAINS_BLOCK
-	LIST_ITEM_BEGINNING_OF_LIST
-	LIST_ITEM_END_OF_LIST
-)
-
-// These are the possible flag values for the table cell renderer.
-// Only a single one of these values will be used; they are not ORed together.
-// These are mostly of interest if you are writing a new output format.
-const (
-	TABLE_ALIGNMENT_LEFT = 1 << iota
-	TABLE_ALIGNMENT_RIGHT
-	TABLE_ALIGNMENT_CENTER = (TABLE_ALIGNMENT_LEFT | TABLE_ALIGNMENT_RIGHT)
-)
-
-// The size of a tab stop.
-const (
-	TAB_SIZE_DEFAULT = 4
-	TAB_SIZE_EIGHT   = 8
-)
-
-// blockTags is a set of tags that are recognized as HTML block tags.
-// Any of these can be included in markdown text without special escaping.
-var blockTags = map[string]struct{}{
-	"blockquote": {},
-	"del":        {},
-	"div":        {},
-	"dl":         {},
-	"fieldset":   {},
-	"form":       {},
-	"h1":         {},
-	"h2":         {},
-	"h3":         {},
-	"h4":         {},
-	"h5":         {},
-	"h6":         {},
-	"iframe":     {},
-	"ins":        {},
-	"math":       {},
-	"noscript":   {},
-	"ol":         {},
-	"pre":        {},
-	"p":          {},
-	"script":     {},
-	"style":      {},
-	"table":      {},
-	"ul":         {},
-
-	// HTML5
-	"address":    {},
-	"article":    {},
-	"aside":      {},
-	"canvas":     {},
-	"figcaption": {},
-	"figure":     {},
-	"footer":     {},
-	"header":     {},
-	"hgroup":     {},
-	"main":       {},
-	"nav":        {},
-	"output":     {},
-	"progress":   {},
-	"section":    {},
-	"video":      {},
-}
-
-// Renderer is the rendering interface.
-// This is mostly of interest if you are implementing a new rendering format.
-//
-// When a byte slice is provided, it contains the (rendered) contents of the
-// element.
-//
-// When a callback is provided instead, it will write the contents of the
-// respective element directly to the output buffer and return true on success.
-// If the callback returns false, the rendering function should reset the
-// output buffer as though it had never been called.
-//
-// Currently Html and Latex implementations are provided
-type Renderer interface {
-	// block-level callbacks
-	BlockCode(out *bytes.Buffer, text []byte, lang string)
-	BlockQuote(out *bytes.Buffer, text []byte)
-	BlockHtml(out *bytes.Buffer, text []byte)
-	Header(out *bytes.Buffer, text func() bool, level int, id string)
-	HRule(out *bytes.Buffer)
-	List(out *bytes.Buffer, text func() bool, flags int)
-	ListItem(out *bytes.Buffer, text []byte, flags int)
-	Paragraph(out *bytes.Buffer, text func() bool)
-	Table(out *bytes.Buffer, header []byte, body []byte, columnData []int)
-	TableRow(out *bytes.Buffer, text []byte)
-	TableHeaderCell(out *bytes.Buffer, text []byte, flags int)
-	TableCell(out *bytes.Buffer, text []byte, flags int)
-	Footnotes(out *bytes.Buffer, text func() bool)
-	FootnoteItem(out *bytes.Buffer, name, text []byte, flags int)
-	TitleBlock(out *bytes.Buffer, text []byte)
-
-	// Span-level callbacks
-	AutoLink(out *bytes.Buffer, link []byte, kind int)
-	CodeSpan(out *bytes.Buffer, text []byte)
-	DoubleEmphasis(out *bytes.Buffer, text []byte)
-	Emphasis(out *bytes.Buffer, text []byte)
-	Image(out *bytes.Buffer, link []byte, title []byte, alt []byte)
-	LineBreak(out *bytes.Buffer)
-	Link(out *bytes.Buffer, link []byte, title []byte, content []byte)
-	RawHtmlTag(out *bytes.Buffer, tag []byte)
-	TripleEmphasis(out *bytes.Buffer, text []byte)
-	StrikeThrough(out *bytes.Buffer, text []byte)
-	FootnoteRef(out *bytes.Buffer, ref []byte, id int)
-
-	// Low-level callbacks
-	Entity(out *bytes.Buffer, entity []byte)
-	NormalText(out *bytes.Buffer, text []byte)
-
-	// Header and footer
-	DocumentHeader(out *bytes.Buffer)
-	DocumentFooter(out *bytes.Buffer)
-
-	GetFlags() int
-}
-
-// Callback functions for inline parsing. One such function is defined
-// for each character that triggers a response when parsing inline data.
-type inlineParser func(p *parser, out *bytes.Buffer, data []byte, offset int) int
-
-// Parser holds runtime state used by the parser.
-// This is constructed by the Markdown function.
-type parser struct {
-	r              Renderer
-	refOverride    ReferenceOverrideFunc
-	refs           map[string]*reference
-	inlineCallback [256]inlineParser
-	flags          int
-	nesting        int
-	maxNesting     int
-	insideLink     bool
-
-	// Footnotes need to be ordered as well as available to quickly check for
-	// presence. If a ref is also a footnote, it's stored both in refs and here
-	// in notes. Slice is nil if footnotes not enabled.
-	notes []*reference
-}
-
-func (p *parser) getRef(refid string) (ref *reference, found bool) {
-	if p.refOverride != nil {
-		r, overridden := p.refOverride(refid)
-		if overridden {
-			if r == nil {
-				return nil, false
-			}
-			return &reference{
-				link:     []byte(r.Link),
-				title:    []byte(r.Title),
-				noteId:   0,
-				hasBlock: false,
-				text:     []byte(r.Text)}, true
-		}
-	}
-	// refs are case insensitive
-	ref, found = p.refs[strings.ToLower(refid)]
-	return ref, found
-}
-
-//
-//
-// Public interface
-//
-//
-
-// Reference represents the details of a link.
-// See the documentation in Options for more details on use-case.
-type Reference struct {
-	// Link is usually the URL the reference points to.
-	Link string
-	// Title is the alternate text describing the link in more detail.
-	Title string
-	// Text is the optional text to override the ref with if the syntax used was
-	// [refid][]
-	Text string
-}
-
-// ReferenceOverrideFunc is expected to be called with a reference string and
-// return either a valid Reference type that the reference string maps to or
-// nil. If overridden is false, the default reference logic will be executed.
-// See the documentation in Options for more details on use-case.
-type ReferenceOverrideFunc func(reference string) (ref *Reference, overridden bool)
-
-// Options represents configurable overrides and callbacks (in addition to the
-// extension flag set) for configuring a Markdown parse.
-type Options struct {
-	// Extensions is a flag set of bit-wise ORed extension bits. See the
-	// EXTENSION_* flags defined in this package.
-	Extensions int
-
-	// ReferenceOverride is an optional function callback that is called every
-	// time a reference is resolved.
-	//
-	// In Markdown, the link reference syntax can be made to resolve a link to
-	// a reference instead of an inline URL, in one of the following ways:
-	//
-	//  * [link text][refid]
-	//  * [refid][]
-	//
-	// Usually, the refid is defined at the bottom of the Markdown document. If
-	// this override function is provided, the refid is passed to the override
-	// function first, before consulting the defined refids at the bottom. If
-	// the override function indicates an override did not occur, the refids at
-	// the bottom will be used to fill in the link details.
-	ReferenceOverride ReferenceOverrideFunc
-}
-
-// MarkdownBasic is a convenience function for simple rendering.
-// It processes markdown input with no extensions enabled.
-func MarkdownBasic(input []byte) []byte {
-	// set up the HTML renderer
-	htmlFlags := HTML_USE_XHTML
-	renderer := HtmlRenderer(htmlFlags, "", "")
-
-	// set up the parser
-	return MarkdownOptions(input, renderer, Options{Extensions: 0})
-}
-
-// Call Markdown with most useful extensions enabled
-// MarkdownCommon is a convenience function for simple rendering.
-// It processes markdown input with common extensions enabled, including:
-//
-// * Smartypants processing with smart fractions and LaTeX dashes
-//
-// * Intra-word emphasis suppression
-//
-// * Tables
-//
-// * Fenced code blocks
-//
-// * Autolinking
-//
-// * Strikethrough support
-//
-// * Strict header parsing
-//
-// * Custom Header IDs
-func MarkdownCommon(input []byte) []byte {
-	// set up the HTML renderer
-	renderer := HtmlRenderer(commonHtmlFlags, "", "")
-	return MarkdownOptions(input, renderer, Options{
-		Extensions: commonExtensions})
-}
-
-// Markdown is the main rendering function.
-// It parses and renders a block of markdown-encoded text.
-// The supplied Renderer is used to format the output, and extensions dictates
-// which non-standard extensions are enabled.
-//
-// To use the supplied Html or LaTeX renderers, see HtmlRenderer and
-// LatexRenderer, respectively.
-func Markdown(input []byte, renderer Renderer, extensions int) []byte {
-	return MarkdownOptions(input, renderer, Options{
-		Extensions: extensions})
-}
-
-// MarkdownOptions is just like Markdown but takes additional options through
-// the Options struct.
-func MarkdownOptions(input []byte, renderer Renderer, opts Options) []byte {
-	// no point in parsing if we can't render
-	if renderer == nil {
-		return nil
-	}
-
-	extensions := opts.Extensions
-
-	// fill in the render structure
-	p := new(parser)
-	p.r = renderer
-	p.flags = extensions
-	p.refOverride = opts.ReferenceOverride
-	p.refs = make(map[string]*reference)
-	p.maxNesting = 16
-	p.insideLink = false
-
-	// register inline parsers
-	p.inlineCallback['*'] = emphasis
-	p.inlineCallback['_'] = emphasis
-	if extensions&EXTENSION_STRIKETHROUGH != 0 {
-		p.inlineCallback['~'] = emphasis
-	}
-	p.inlineCallback['`'] = codeSpan
-	p.inlineCallback['\n'] = lineBreak
-	p.inlineCallback['['] = link
-	p.inlineCallback['<'] = leftAngle
-	p.inlineCallback['\\'] = escape
-	p.inlineCallback['&'] = entity
-
-	if extensions&EXTENSION_AUTOLINK != 0 {
-		p.inlineCallback[':'] = autoLink
-	}
-
-	if extensions&EXTENSION_FOOTNOTES != 0 {
-		p.notes = make([]*reference, 0)
-	}
-
-	first := firstPass(p, input)
-	second := secondPass(p, first)
-	return second
-}
-
-// first pass:
-// - extract references
-// - expand tabs
-// - normalize newlines
-// - copy everything else
-func firstPass(p *parser, input []byte) []byte {
-	var out bytes.Buffer
-	tabSize := TAB_SIZE_DEFAULT
-	if p.flags&EXTENSION_TAB_SIZE_EIGHT != 0 {
-		tabSize = TAB_SIZE_EIGHT
-	}
-	beg, end := 0, 0
-	lastFencedCodeBlockEnd := 0
-	for beg < len(input) { // iterate over lines
-		if end = isReference(p, input[beg:], tabSize); end > 0 {
-			beg += end
-		} else { // skip to the next line
-			end = beg
-			for end < len(input) && input[end] != '\n' && input[end] != '\r' {
-				end++
-			}
-
-			if p.flags&EXTENSION_FENCED_CODE != 0 {
-				// track fenced code block boundaries to suppress tab expansion
-				// inside them:
-				if beg >= lastFencedCodeBlockEnd {
-					if i := p.fencedCode(&out, input[beg:], false); i > 0 {
-						lastFencedCodeBlockEnd = beg + i
-					}
-				}
-			}
-
-			// add the line body if present
-			if end > beg {
-				if end < lastFencedCodeBlockEnd { // Do not expand tabs while inside fenced code blocks.
-					out.Write(input[beg:end])
-				} else {
-					expandTabs(&out, input[beg:end], tabSize)
-				}
-			}
-			out.WriteByte('\n')
-
-			if end < len(input) && input[end] == '\r' {
-				end++
-			}
-			if end < len(input) && input[end] == '\n' {
-				end++
-			}
-
-			beg = end
-		}
-	}
-
-	// empty input?
-	if out.Len() == 0 {
-		out.WriteByte('\n')
-	}
-
-	return out.Bytes()
-}
-
-// second pass: actual rendering
-func secondPass(p *parser, input []byte) []byte {
-	var output bytes.Buffer
-
-	p.r.DocumentHeader(&output)
-	p.block(&output, input)
-
-	if p.flags&EXTENSION_FOOTNOTES != 0 && len(p.notes) > 0 {
-		p.r.Footnotes(&output, func() bool {
-			flags := LIST_ITEM_BEGINNING_OF_LIST
-			for i := 0; i < len(p.notes); i += 1 {
-				ref := p.notes[i]
-				var buf bytes.Buffer
-				if ref.hasBlock {
-					flags |= LIST_ITEM_CONTAINS_BLOCK
-					p.block(&buf, ref.title)
-				} else {
-					p.inline(&buf, ref.title)
-				}
-				p.r.FootnoteItem(&output, ref.link, buf.Bytes(), flags)
-				flags &^= LIST_ITEM_BEGINNING_OF_LIST | LIST_ITEM_CONTAINS_BLOCK
-			}
-
-			return true
-		})
-	}
-
-	p.r.DocumentFooter(&output)
-
-	if p.nesting != 0 {
-		panic("Nesting level did not end at zero")
-	}
-
-	return output.Bytes()
-}
-
-//
-// Link references
-//
-// This section implements support for references that (usually) appear
-// as footnotes in a document, and can be referenced anywhere in the document.
-// The basic format is:
-//
-//    [1]: http://www.google.com/ "Google"
-//    [2]: http://www.github.com/ "Github"
-//
-// Anywhere in the document, the reference can be linked by referring to its
-// label, i.e., 1 and 2 in this example, as in:
-//
-//    This library is hosted on [Github][2], a git hosting site.
-//
-// Actual footnotes as specified in Pandoc and supported by some other Markdown
-// libraries such as php-markdown are also taken care of. They look like this:
-//
-//    This sentence needs a bit of further explanation.[^note]
-//
-//    [^note]: This is the explanation.
-//
-// Footnotes should be placed at the end of the document in an ordered list.
-// Inline footnotes such as:
-//
-//    Inline footnotes^[Not supported.] also exist.
-//
-// are not yet supported.
-
-// References are parsed and stored in this struct.
-type reference struct {
-	link     []byte
-	title    []byte
-	noteId   int // 0 if not a footnote ref
-	hasBlock bool
-	text     []byte
-}
-
-func (r *reference) String() string {
-	return fmt.Sprintf("{link: %q, title: %q, text: %q, noteId: %d, hasBlock: %v}",
-		r.link, r.title, r.text, r.noteId, r.hasBlock)
-}
-
-// Check whether or not data starts with a reference link.
-// If so, it is parsed and stored in the list of references
-// (in the render struct).
-// Returns the number of bytes to skip to move past it,
-// or zero if the first line is not a reference.
-func isReference(p *parser, data []byte, tabSize int) int {
-	// up to 3 optional leading spaces
-	if len(data) < 4 {
-		return 0
-	}
-	i := 0
-	for i < 3 && data[i] == ' ' {
-		i++
-	}
-
-	noteId := 0
-
-	// id part: anything but a newline between brackets
-	if data[i] != '[' {
-		return 0
-	}
-	i++
-	if p.flags&EXTENSION_FOOTNOTES != 0 {
-		if i < len(data) && data[i] == '^' {
-			// we can set it to anything here because the proper noteIds will
-			// be assigned later during the second pass. It just has to be != 0
-			noteId = 1
-			i++
-		}
-	}
-	idOffset := i
-	for i < len(data) && data[i] != '\n' && data[i] != '\r' && data[i] != ']' {
-		i++
-	}
-	if i >= len(data) || data[i] != ']' {
-		return 0
-	}
-	idEnd := i
-
-	// spacer: colon (space | tab)* newline? (space | tab)*
-	i++
-	if i >= len(data) || data[i] != ':' {
-		return 0
-	}
-	i++
-	for i < len(data) && (data[i] == ' ' || data[i] == '\t') {
-		i++
-	}
-	if i < len(data) && (data[i] == '\n' || data[i] == '\r') {
-		i++
-		if i < len(data) && data[i] == '\n' && data[i-1] == '\r' {
-			i++
-		}
-	}
-	for i < len(data) && (data[i] == ' ' || data[i] == '\t') {
-		i++
-	}
-	if i >= len(data) {
-		return 0
-	}
-
-	var (
-		linkOffset, linkEnd   int
-		titleOffset, titleEnd int
-		lineEnd               int
-		raw                   []byte
-		hasBlock              bool
-	)
-
-	if p.flags&EXTENSION_FOOTNOTES != 0 && noteId != 0 {
-		linkOffset, linkEnd, raw, hasBlock = scanFootnote(p, data, i, tabSize)
-		lineEnd = linkEnd
-	} else {
-		linkOffset, linkEnd, titleOffset, titleEnd, lineEnd = scanLinkRef(p, data, i)
-	}
-	if lineEnd == 0 {
-		return 0
-	}
-
-	// a valid ref has been found
-
-	ref := &reference{
-		noteId:   noteId,
-		hasBlock: hasBlock,
-	}
-
-	if noteId > 0 {
-		// reusing the link field for the id since footnotes don't have links
-		ref.link = data[idOffset:idEnd]
-		// if footnote, it's not really a title, it's the contained text
-		ref.title = raw
-	} else {
-		ref.link = data[linkOffset:linkEnd]
-		ref.title = data[titleOffset:titleEnd]
-	}
-
-	// id matches are case-insensitive
-	id := string(bytes.ToLower(data[idOffset:idEnd]))
-
-	p.refs[id] = ref
-
-	return lineEnd
-}
-
-func scanLinkRef(p *parser, data []byte, i int) (linkOffset, linkEnd, titleOffset, titleEnd, lineEnd int) {
-	// link: whitespace-free sequence, optionally between angle brackets
-	if data[i] == '<' {
-		i++
-	}
-	linkOffset = i
-	if i == len(data) {
-		return
-	}
-	for i < len(data) && data[i] != ' ' && data[i] != '\t' && data[i] != '\n' && data[i] != '\r' {
-		i++
-	}
-	linkEnd = i
-	if data[linkOffset] == '<' && data[linkEnd-1] == '>' {
-		linkOffset++
-		linkEnd--
-	}
-
-	// optional spacer: (space | tab)* (newline | '\'' | '"' | '(' )
-	for i < len(data) && (data[i] == ' ' || data[i] == '\t') {
-		i++
-	}
-	if i < len(data) && data[i] != '\n' && data[i] != '\r' && data[i] != '\'' && data[i] != '"' && data[i] != '(' {
-		return
-	}
-
-	// compute end-of-line
-	if i >= len(data) || data[i] == '\r' || data[i] == '\n' {
-		lineEnd = i
-	}
-	if i+1 < len(data) && data[i] == '\r' && data[i+1] == '\n' {
-		lineEnd++
-	}
-
-	// optional (space|tab)* spacer after a newline
-	if lineEnd > 0 {
-		i = lineEnd + 1
-		for i < len(data) && (data[i] == ' ' || data[i] == '\t') {
-			i++
-		}
-	}
-
-	// optional title: any non-newline sequence enclosed in '"() alone on its line
-	if i+1 < len(data) && (data[i] == '\'' || data[i] == '"' || data[i] == '(') {
-		i++
-		titleOffset = i
-
-		// look for EOL
-		for i < len(data) && data[i] != '\n' && data[i] != '\r' {
-			i++
-		}
-		if i+1 < len(data) && data[i] == '\n' && data[i+1] == '\r' {
-			titleEnd = i + 1
-		} else {
-			titleEnd = i
-		}
-
-		// step back
-		i--
-		for i > titleOffset && (data[i] == ' ' || data[i] == '\t') {
-			i--
-		}
-		if i > titleOffset && (data[i] == '\'' || data[i] == '"' || data[i] == ')') {
-			lineEnd = titleEnd
-			titleEnd = i
-		}
-	}
-
-	return
-}
-
-// The first bit of this logic is the same as (*parser).listItem, but the rest
-// is much simpler. This function simply finds the entire block and shifts it
-// over by one tab if it is indeed a block (just returns the line if it's not).
-// blockEnd is the end of the section in the input buffer, and contents is the
-// extracted text that was shifted over one tab. It will need to be rendered at
-// the end of the document.
-func scanFootnote(p *parser, data []byte, i, indentSize int) (blockStart, blockEnd int, contents []byte, hasBlock bool) {
-	if i == 0 || len(data) == 0 {
-		return
-	}
-
-	// skip leading whitespace on first line
-	for i < len(data) && data[i] == ' ' {
-		i++
-	}
-
-	blockStart = i
-
-	// find the end of the line
-	blockEnd = i
-	for i < len(data) && data[i-1] != '\n' {
-		i++
-	}
-
-	// get working buffer
-	var raw bytes.Buffer
-
-	// put the first line into the working buffer
-	raw.Write(data[blockEnd:i])
-	blockEnd = i
-
-	// process the following lines
-	containsBlankLine := false
-
-gatherLines:
-	for blockEnd < len(data) {
-		i++
-
-		// find the end of this line
-		for i < len(data) && data[i-1] != '\n' {
-			i++
-		}
-
-		// if it is an empty line, guess that it is part of this item
-		// and move on to the next line
-		if p.isEmpty(data[blockEnd:i]) > 0 {
-			containsBlankLine = true
-			blockEnd = i
-			continue
-		}
-
-		n := 0
-		if n = isIndented(data[blockEnd:i], indentSize); n == 0 {
-			// this is the end of the block.
-			// we don't want to include this last line in the index.
-			break gatherLines
-		}
-
-		// if there were blank lines before this one, insert a new one now
-		if containsBlankLine {
-			raw.WriteByte('\n')
-			containsBlankLine = false
-		}
-
-		// get rid of that first tab, write to buffer
-		raw.Write(data[blockEnd+n : i])
-		hasBlock = true
-
-		blockEnd = i
-	}
-
-	if data[blockEnd-1] != '\n' {
-		raw.WriteByte('\n')
-	}
-
-	contents = raw.Bytes()
-
-	return
-}
-
-//
-//
-// Miscellaneous helper functions
-//
-//
-
-// Test if a character is a punctuation symbol.
-// Taken from a private function in regexp in the stdlib.
-func ispunct(c byte) bool {
-	for _, r := range []byte("!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~") {
-		if c == r {
-			return true
-		}
-	}
-	return false
-}
-
-// Test if a character is a whitespace character.
-func isspace(c byte) bool {
-	return c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == '\f' || c == '\v'
-}
-
-// Test if a character is letter.
-func isletter(c byte) bool {
-	return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')
-}
-
-// Test if a character is a letter or a digit.
-// TODO: check when this is looking for ASCII alnum and when it should use unicode
-func isalnum(c byte) bool {
-	return (c >= '0' && c <= '9') || isletter(c)
-}
-
-// Replace tab characters with spaces, aligning to the next TAB_SIZE column.
-// always ends output with a newline
-func expandTabs(out *bytes.Buffer, line []byte, tabSize int) {
-	// first, check for common cases: no tabs, or only tabs at beginning of line
-	i, prefix := 0, 0
-	slowcase := false
-	for i = 0; i < len(line); i++ {
-		if line[i] == '\t' {
-			if prefix == i {
-				prefix++
-			} else {
-				slowcase = true
-				break
-			}
-		}
-	}
-
-	// no need to decode runes if all tabs are at the beginning of the line
-	if !slowcase {
-		for i = 0; i < prefix*tabSize; i++ {
-			out.WriteByte(' ')
-		}
-		out.Write(line[prefix:])
-		return
-	}
-
-	// the slow case: we need to count runes to figure out how
-	// many spaces to insert for each tab
-	column := 0
-	i = 0
-	for i < len(line) {
-		start := i
-		for i < len(line) && line[i] != '\t' {
-			_, size := utf8.DecodeRune(line[i:])
-			i += size
-			column++
-		}
-
-		if i > start {
-			out.Write(line[start:i])
-		}
-
-		if i >= len(line) {
-			break
-		}
-
-		for {
-			out.WriteByte(' ')
-			column++
-			if column%tabSize == 0 {
-				break
-			}
-		}
-
-		i++
-	}
-}
-
-// Find if a line counts as indented or not.
-// Returns number of characters the indent is (0 = not indented).
-func isIndented(data []byte, indentSize int) int {
-	if len(data) == 0 {
-		return 0
-	}
-	if data[0] == '\t' {
-		return 1
-	}
-	if len(data) < indentSize {
-		return 0
-	}
-	for i := 0; i < indentSize; i++ {
-		if data[i] != ' ' {
-			return 0
-		}
-	}
-	return indentSize
-}
-
-// Create a url-safe slug for fragments
-func slugify(in []byte) []byte {
-	if len(in) == 0 {
-		return in
-	}
-	out := make([]byte, 0, len(in))
-	sym := false
-
-	for _, ch := range in {
-		if isalnum(ch) {
-			sym = false
-			out = append(out, ch)
-		} else if sym {
-			continue
-		} else {
-			out = append(out, '-')
-			sym = true
-		}
-	}
-	var a, b int
-	var ch byte
-	for a, ch = range out {
-		if ch != '-' {
-			break
-		}
-	}
-	for b = len(out) - 1; b > 0; b-- {
-		if out[b] != '-' {
-			break
-		}
-	}
-	return out[a : b+1]
-}
diff --git a/vendor/github.com/russross/blackfriday/LICENSE.txt b/vendor/github.com/russross/blackfriday/v2/LICENSE.txt
similarity index 100%
rename from vendor/github.com/russross/blackfriday/LICENSE.txt
rename to vendor/github.com/russross/blackfriday/v2/LICENSE.txt
diff --git a/vendor/github.com/russross/blackfriday/README.md b/vendor/github.com/russross/blackfriday/v2/README.md
similarity index 70%
rename from vendor/github.com/russross/blackfriday/README.md
rename to vendor/github.com/russross/blackfriday/v2/README.md
index 1879ce71b0..d5a8649bd5 100644
--- a/vendor/github.com/russross/blackfriday/README.md
+++ b/vendor/github.com/russross/blackfriday/v2/README.md
@@ -1,4 +1,4 @@
-Blackfriday [![Build Status](https://travis-ci.org/russross/blackfriday.svg?branch=master)](https://travis-ci.org/russross/blackfriday) [![GoDoc](https://godoc.org/github.com/russross/blackfriday?status.svg)](https://godoc.org/github.com/russross/blackfriday)
+Blackfriday [![Build Status](https://travis-ci.org/russross/blackfriday.svg?branch=master)](https://travis-ci.org/russross/blackfriday)
 ===========
 
 Blackfriday is a [Markdown][1] processor implemented in [Go][2]. It
@@ -8,7 +8,7 @@ punctuation substitutions, etc.), and it is safe for all utf-8
 (unicode) input.
 
 HTML output is currently supported, along with Smartypants
-extensions. An experimental LaTeX output engine is also included.
+extensions.
 
 It started as a translation from C of [Sundown][3].
 
@@ -16,63 +16,93 @@ It started as a translation from C of [Sundown][3].
 Installation
 ------------
 
-Blackfriday is compatible with Go 1. If you are using an older
-release of Go, consider using v1.1 of blackfriday, which was based
-on the last stable release of Go prior to Go 1. You can find it as a
-tagged commit on github.
+Blackfriday is compatible with any modern Go release. With Go 1.7 and git
+installed:
 
-With Go 1 and git installed:
-
-    go get github.com/russross/blackfriday
+    go get gopkg.in/russross/blackfriday.v2
 
 will download, compile, and install the package into your `$GOPATH`
 directory hierarchy. Alternatively, you can achieve the same if you
 import it into a project:
 
-    import "github.com/russross/blackfriday"
+    import "gopkg.in/russross/blackfriday.v2"
 
 and `go get` without parameters.
 
+
+Versions
+--------
+
+Currently maintained and recommended version of Blackfriday is `v2`. It's being
+developed on its own branch: https://github.com/russross/blackfriday/tree/v2 and the
+documentation is available at
+https://godoc.org/gopkg.in/russross/blackfriday.v2.
+
+It is `go get`-able via via [gopkg.in][6] at `gopkg.in/russross/blackfriday.v2`,
+but we highly recommend using package management tool like [dep][7] or
+[Glide][8] and make use of semantic versioning. With package management you
+should import `github.com/russross/blackfriday` and specify that you're using
+version 2.0.0.
+
+Version 2 offers a number of improvements over v1:
+
+* Cleaned up API
+* A separate call to [`Parse`][4], which produces an abstract syntax tree for
+  the document
+* Latest bug fixes
+* Flexibility to easily add your own rendering extensions
+
+Potential drawbacks:
+
+* Our benchmarks show v2 to be slightly slower than v1. Currently in the
+  ballpark of around 15%.
+* API breakage. If you can't afford modifying your code to adhere to the new API
+  and don't care too much about the new features, v2 is probably not for you.
+* Several bug fixes are trailing behind and still need to be forward-ported to
+  v2. See issue [#348](https://github.com/russross/blackfriday/issues/348) for
+  tracking.
+
 Usage
 -----
 
-For basic usage, it is as simple as getting your input into a byte
-slice and calling:
+For the most sensible markdown processing, it is as simple as getting your input
+into a byte slice and calling:
 
-    output := blackfriday.MarkdownBasic(input)
+```go
+output := blackfriday.Run(input)
+```
 
-This renders it with no extensions enabled. To get a more useful
-feature set, use this instead:
+Your input will be parsed and the output rendered with a set of most popular
+extensions enabled. If you want the most basic feature set, corresponding with
+the bare Markdown specification, use:
 
-    output := blackfriday.MarkdownCommon(input)
+```go
+output := blackfriday.Run(input, blackfriday.WithNoExtensions())
+```
 
 ### Sanitize untrusted content
 
 Blackfriday itself does nothing to protect against malicious content. If you are
-dealing with user-supplied markdown, we recommend running blackfriday's output
-through HTML sanitizer such as
-[Bluemonday](https://github.com/microcosm-cc/bluemonday).
+dealing with user-supplied markdown, we recommend running Blackfriday's output
+through HTML sanitizer such as [Bluemonday][5].
 
-Here's an example of simple usage of blackfriday together with bluemonday:
+Here's an example of simple usage of Blackfriday together with Bluemonday:
 
-``` go
+```go
 import (
     "github.com/microcosm-cc/bluemonday"
     "github.com/russross/blackfriday"
 )
 
 // ...
-unsafe := blackfriday.MarkdownCommon(input)
+unsafe := blackfriday.Run(input)
 html := bluemonday.UGCPolicy().SanitizeBytes(unsafe)
 ```
 
 ### Custom options
 
-If you want to customize the set of options, first get a renderer
-(currently either the HTML or LaTeX output engines), then use it to
-call the more general `Markdown` function. For examples, see the
-implementations of `MarkdownBasic` and `MarkdownCommon` in
-`markdown.go`.
+If you want to customize the set of options, use `blackfriday.WithExtensions`,
+`blackfriday.WithRenderer` and `blackfriday.WithRefOverride`.
 
 You can also check out `blackfriday-tool` for a more complete example
 of how to use it. Download and install it using:
@@ -160,7 +190,7 @@ implements the following extensions:
     and supply a language (to make syntax highlighting simple). Just
     mark it like this:
 
-        ``` go
+        ```go
         func getTrue() bool {
             return true
         }
@@ -174,7 +204,7 @@ implements the following extensions:
 
         Cat
         : Fluffy animal everyone likes
-        
+
         Internet
         : Vector of transmission for pictures of cats
 
@@ -185,7 +215,7 @@ implements the following extensions:
     end of the document. A footnote looks like this:
 
         This is a footnote.[^1]
-        
+
         [^1]: the footnote text.
 
 *   **Autolinking**. Blackfriday can find URLs that have not been
@@ -194,10 +224,8 @@ implements the following extensions:
 *   **Strikethrough**. Use two tildes (`~~`) to mark text that
     should be crossed out.
 
-*   **Hard line breaks**. With this extension enabled (it is off by
-    default in the `MarkdownBasic` and `MarkdownCommon` convenience
-    functions), newlines in the input translate into line breaks in
-    the output.
+*   **Hard line breaks**. With this extension enabled newlines in the input
+    translate into line breaks in the output. This extension is off by default.
 
 *   **Smart quotes**. Smartypants-style punctuation substitution is
     supported, turning normal double- and single-quote marks into
@@ -224,7 +252,7 @@ are a few of note:
 
 *   [github_flavored_markdown](https://godoc.org/github.com/shurcooL/github_flavored_markdown):
     provides a GitHub Flavored Markdown renderer with fenced code block
-    highlighting, clickable header anchor links.
+    highlighting, clickable heading anchor links.
 
     It's not customizable, and its goal is to produce HTML output
     equivalent to the [GitHub Markdown API endpoint](https://developer.github.com/v3/markdown/#render-a-markdown-document-in-raw-mode),
@@ -233,17 +261,10 @@ are a few of note:
 *   [markdownfmt](https://github.com/shurcooL/markdownfmt): like gofmt,
     but for markdown.
 
-*   LaTeX output: renders output as LaTeX. This is currently part of the
-    main Blackfriday repository, but may be split into its own project
-    in the future. If you are interested in owning and maintaining the
-    LaTeX output component, please be in touch.
+*   [LaTeX output](https://github.com/Ambrevar/Blackfriday-LaTeX):
+    renders output as LaTeX.
 
-    It renders some basic documents, but is only experimental at this
-    point. In particular, it does not do any inline escaping, so input
-    that happens to look like LaTeX code will be passed through without
-    modification.
-    
-*   [Md2Vim](https://github.com/FooSoft/md2vim): transforms markdown files into vimdoc format.
+*   [Blackfriday-Confluence](https://github.com/kentaro-m/blackfriday-confluence): provides a [Confluence Wiki Markup](https://confluence.atlassian.com/doc/confluence-wiki-markup-251003035.html) renderer.
 
 
 Todo
@@ -262,6 +283,9 @@ License
 [Blackfriday is distributed under the Simplified BSD License](LICENSE.txt)
 
 
-   [1]: http://daringfireball.net/projects/markdown/ "Markdown"
-   [2]: http://golang.org/ "Go Language"
+   [1]: https://daringfireball.net/projects/markdown/ "Markdown"
+   [2]: https://golang.org/ "Go Language"
    [3]: https://github.com/vmg/sundown "Sundown"
+   [4]: https://godoc.org/gopkg.in/russross/blackfriday.v2#Parse "Parse func"
+   [5]: https://github.com/microcosm-cc/bluemonday "Bluemonday"
+   [6]: https://labix.org/gopkg.in "gopkg.in"
diff --git a/vendor/github.com/russross/blackfriday/block.go b/vendor/github.com/russross/blackfriday/v2/block.go
similarity index 51%
rename from vendor/github.com/russross/blackfriday/block.go
rename to vendor/github.com/russross/blackfriday/v2/block.go
index 3f4af787e3..b8607474e5 100644
--- a/vendor/github.com/russross/blackfriday/block.go
+++ b/vendor/github.com/russross/blackfriday/v2/block.go
@@ -15,18 +15,27 @@ package blackfriday
 
 import (
 	"bytes"
+	"html"
+	"regexp"
+	"strings"
 
 	"github.com/shurcooL/sanitized_anchor_name"
 )
 
+const (
+	charEntity = "&(?:#x[a-f0-9]{1,8}|#[0-9]{1,8}|[a-z][a-z0-9]{1,31});"
+	escapable  = "[!\"#$%&'()*+,./:;<=>?@[\\\\\\]^_`{|}~-]"
+)
+
+var (
+	reBackslashOrAmp      = regexp.MustCompile("[\\&]")
+	reEntityOrEscapedChar = regexp.MustCompile("(?i)\\\\" + escapable + "|" + charEntity)
+)
+
 // Parse block-level data.
 // Note: this function and many that it calls assume that
 // the input buffer ends with a newline.
-func (p *parser) block(out *bytes.Buffer, data []byte) {
-	if len(data) == 0 || data[len(data)-1] != '\n' {
-		panic("block input is missing terminating newline")
-	}
-
+func (p *Markdown) block(data []byte) {
 	// this is called recursively: enforce a maximum depth
 	if p.nesting >= p.maxNesting {
 		return
@@ -35,14 +44,14 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 
 	// parse out one block-level construct at a time
 	for len(data) > 0 {
-		// prefixed header:
+		// prefixed heading:
 		//
-		// # Header 1
-		// ## Header 2
+		// # Heading 1
+		// ## Heading 2
 		// ...
-		// ###### Header 6
-		if p.isPrefixHeader(data) {
-			data = data[p.prefixHeader(out, data):]
+		// ###### Heading 6
+		if p.isPrefixHeading(data) {
+			data = data[p.prefixHeading(data):]
 			continue
 		}
 
@@ -52,7 +61,7 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		//     ...
 		// </div>
 		if data[0] == '<' {
-			if i := p.html(out, data, true); i > 0 {
+			if i := p.html(data, true); i > 0 {
 				data = data[i:]
 				continue
 			}
@@ -63,9 +72,9 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		// % stuff
 		// % more stuff
 		// % even more stuff
-		if p.flags&EXTENSION_TITLEBLOCK != 0 {
+		if p.extensions&Titleblock != 0 {
 			if data[0] == '%' {
-				if i := p.titleBlock(out, data, true); i > 0 {
+				if i := p.titleBlock(data, true); i > 0 {
 					data = data[i:]
 					continue
 				}
@@ -87,7 +96,7 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		//         return b
 		//      }
 		if p.codePrefix(data) > 0 {
-			data = data[p.code(out, data):]
+			data = data[p.code(data):]
 			continue
 		}
 
@@ -101,8 +110,8 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		//     return n * fact(n-1)
 		// }
 		// ```
-		if p.flags&EXTENSION_FENCED_CODE != 0 {
-			if i := p.fencedCode(out, data, true); i > 0 {
+		if p.extensions&FencedCode != 0 {
+			if i := p.fencedCodeBlock(data, true); i > 0 {
 				data = data[i:]
 				continue
 			}
@@ -116,9 +125,9 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		// or
 		// ______
 		if p.isHRule(data) {
-			p.r.HRule(out)
+			p.addBlock(HorizontalRule, nil)
 			var i int
-			for i = 0; data[i] != '\n'; i++ {
+			for i = 0; i < len(data) && data[i] != '\n'; i++ {
 			}
 			data = data[i:]
 			continue
@@ -129,7 +138,7 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		// > A big quote I found somewhere
 		// > on the web
 		if p.quotePrefix(data) > 0 {
-			data = data[p.quote(out, data):]
+			data = data[p.quote(data):]
 			continue
 		}
 
@@ -139,8 +148,8 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		// ------|-----|---------
 		// Bob   | 31  | 555-1234
 		// Alice | 27  | 555-4321
-		if p.flags&EXTENSION_TABLES != 0 {
-			if i := p.table(out, data); i > 0 {
+		if p.extensions&Tables != 0 {
+			if i := p.table(data); i > 0 {
 				data = data[i:]
 				continue
 			}
@@ -153,7 +162,7 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		//
 		// also works with + or -
 		if p.uliPrefix(data) > 0 {
-			data = data[p.list(out, data, 0):]
+			data = data[p.list(data, 0):]
 			continue
 		}
 
@@ -162,7 +171,7 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		// 1. Item 1
 		// 2. Item 2
 		if p.oliPrefix(data) > 0 {
-			data = data[p.list(out, data, LIST_TYPE_ORDERED):]
+			data = data[p.list(data, ListTypeOrdered):]
 			continue
 		}
 
@@ -174,55 +183,62 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		//
 		// Term 2
 		// :   Definition c
-		if p.flags&EXTENSION_DEFINITION_LISTS != 0 {
+		if p.extensions&DefinitionLists != 0 {
 			if p.dliPrefix(data) > 0 {
-				data = data[p.list(out, data, LIST_TYPE_DEFINITION):]
+				data = data[p.list(data, ListTypeDefinition):]
 				continue
 			}
 		}
 
 		// anything else must look like a normal paragraph
-		// note: this finds underlined headers, too
-		data = data[p.paragraph(out, data):]
+		// note: this finds underlined headings, too
+		data = data[p.paragraph(data):]
 	}
 
 	p.nesting--
 }
 
-func (p *parser) isPrefixHeader(data []byte) bool {
+func (p *Markdown) addBlock(typ NodeType, content []byte) *Node {
+	p.closeUnmatchedBlocks()
+	container := p.addChild(typ, 0)
+	container.content = content
+	return container
+}
+
+func (p *Markdown) isPrefixHeading(data []byte) bool {
 	if data[0] != '#' {
 		return false
 	}
 
-	if p.flags&EXTENSION_SPACE_HEADERS != 0 {
+	if p.extensions&SpaceHeadings != 0 {
 		level := 0
-		for level < 6 && data[level] == '#' {
+		for level < 6 && level < len(data) && data[level] == '#' {
 			level++
 		}
-		if data[level] != ' ' {
+		if level == len(data) || data[level] != ' ' {
 			return false
 		}
 	}
 	return true
 }
 
-func (p *parser) prefixHeader(out *bytes.Buffer, data []byte) int {
+func (p *Markdown) prefixHeading(data []byte) int {
 	level := 0
-	for level < 6 && data[level] == '#' {
+	for level < 6 && level < len(data) && data[level] == '#' {
 		level++
 	}
 	i := skipChar(data, level, ' ')
 	end := skipUntilChar(data, i, '\n')
 	skip := end
 	id := ""
-	if p.flags&EXTENSION_HEADER_IDS != 0 {
+	if p.extensions&HeadingIDs != 0 {
 		j, k := 0, 0
-		// find start/end of header id
+		// find start/end of heading id
 		for j = i; j < end-1 && (data[j] != '{' || data[j+1] != '#'); j++ {
 		}
 		for k = j + 1; k < end && data[k] != '}'; k++ {
 		}
-		// extract header id iff found
+		// extract heading id iff found
 		if j < end && k < end {
 			id = string(data[j+2 : k])
 			end = j
@@ -242,45 +258,41 @@ func (p *parser) prefixHeader(out *bytes.Buffer, data []byte) int {
 		end--
 	}
 	if end > i {
-		if id == "" && p.flags&EXTENSION_AUTO_HEADER_IDS != 0 {
+		if id == "" && p.extensions&AutoHeadingIDs != 0 {
 			id = sanitized_anchor_name.Create(string(data[i:end]))
 		}
-		work := func() bool {
-			p.inline(out, data[i:end])
-			return true
-		}
-		p.r.Header(out, work, level, id)
+		block := p.addBlock(Heading, data[i:end])
+		block.HeadingID = id
+		block.Level = level
 	}
 	return skip
 }
 
-func (p *parser) isUnderlinedHeader(data []byte) int {
-	// test of level 1 header
+func (p *Markdown) isUnderlinedHeading(data []byte) int {
+	// test of level 1 heading
 	if data[0] == '=' {
 		i := skipChar(data, 1, '=')
 		i = skipChar(data, i, ' ')
-		if data[i] == '\n' {
+		if i < len(data) && data[i] == '\n' {
 			return 1
-		} else {
-			return 0
 		}
+		return 0
 	}
 
-	// test of level 2 header
+	// test of level 2 heading
 	if data[0] == '-' {
 		i := skipChar(data, 1, '-')
 		i = skipChar(data, i, ' ')
-		if data[i] == '\n' {
+		if i < len(data) && data[i] == '\n' {
 			return 2
-		} else {
-			return 0
 		}
+		return 0
 	}
 
 	return 0
 }
 
-func (p *parser) titleBlock(out *bytes.Buffer, data []byte, doRender bool) int {
+func (p *Markdown) titleBlock(data []byte, doRender bool) int {
 	if data[0] != '%' {
 		return 0
 	}
@@ -294,12 +306,17 @@ func (p *parser) titleBlock(out *bytes.Buffer, data []byte, doRender bool) int {
 	}
 
 	data = bytes.Join(splitData[0:i], []byte("\n"))
-	p.r.TitleBlock(out, data)
+	consumed := len(data)
+	data = bytes.TrimPrefix(data, []byte("% "))
+	data = bytes.Replace(data, []byte("\n% "), []byte("\n"), -1)
+	block := p.addBlock(Heading, data)
+	block.Level = 1
+	block.IsTitleblock = true
 
-	return len(data)
+	return consumed
 }
 
-func (p *parser) html(out *bytes.Buffer, data []byte, doRender bool) int {
+func (p *Markdown) html(data []byte, doRender bool) int {
 	var i, j int
 
 	// identify the opening tag
@@ -311,17 +328,12 @@ func (p *parser) html(out *bytes.Buffer, data []byte, doRender bool) int {
 	// handle special cases
 	if !tagfound {
 		// check for an HTML comment
-		if size := p.htmlComment(out, data, doRender); size > 0 {
+		if size := p.htmlComment(data, doRender); size > 0 {
 			return size
 		}
 
 		// check for an <hr> tag
-		if size := p.htmlHr(out, data, doRender); size > 0 {
-			return size
-		}
-
-		// check for HTML CDATA
-		if size := p.htmlCDATA(out, data, doRender); size > 0 {
+		if size := p.htmlHr(data, doRender); size > 0 {
 			return size
 		}
 
@@ -396,60 +408,42 @@ func (p *parser) html(out *bytes.Buffer, data []byte, doRender bool) int {
 		for end > 0 && data[end-1] == '\n' {
 			end--
 		}
-		p.r.BlockHtml(out, data[:end])
+		finalizeHTMLBlock(p.addBlock(HTMLBlock, data[:end]))
 	}
 
 	return i
 }
 
-func (p *parser) renderHTMLBlock(out *bytes.Buffer, data []byte, start int, doRender bool) int {
-	// html block needs to end with a blank line
-	if i := p.isEmpty(data[start:]); i > 0 {
-		size := start + i
+func finalizeHTMLBlock(block *Node) {
+	block.Literal = block.content
+	block.content = nil
+}
+
+// HTML comment, lax form
+func (p *Markdown) htmlComment(data []byte, doRender bool) int {
+	i := p.inlineHTMLComment(data)
+	// needs to end with a blank line
+	if j := p.isEmpty(data[i:]); j > 0 {
+		size := i + j
 		if doRender {
 			// trim trailing newlines
 			end := size
 			for end > 0 && data[end-1] == '\n' {
 				end--
 			}
-			p.r.BlockHtml(out, data[:end])
+			block := p.addBlock(HTMLBlock, data[:end])
+			finalizeHTMLBlock(block)
 		}
 		return size
 	}
 	return 0
 }
 
-// HTML comment, lax form
-func (p *parser) htmlComment(out *bytes.Buffer, data []byte, doRender bool) int {
-	i := p.inlineHTMLComment(out, data)
-	return p.renderHTMLBlock(out, data, i, doRender)
-}
-
-// HTML CDATA section
-func (p *parser) htmlCDATA(out *bytes.Buffer, data []byte, doRender bool) int {
-	const cdataTag = "<![cdata["
-	const cdataTagLen = len(cdataTag)
-	if len(data) < cdataTagLen+1 {
-		return 0
-	}
-	if !bytes.Equal(bytes.ToLower(data[:cdataTagLen]), []byte(cdataTag)) {
-		return 0
-	}
-	i := cdataTagLen
-	// scan for an end-of-comment marker, across lines if necessary
-	for i < len(data) && !(data[i-2] == ']' && data[i-1] == ']' && data[i] == '>') {
-		i++
-	}
-	i++
-	// no end-of-comment marker
-	if i >= len(data) {
-		return 0
-	}
-	return p.renderHTMLBlock(out, data, i, doRender)
-}
-
 // HR, which is the only self-closing block tag considered
-func (p *parser) htmlHr(out *bytes.Buffer, data []byte, doRender bool) int {
+func (p *Markdown) htmlHr(data []byte, doRender bool) int {
+	if len(data) < 4 {
+		return 0
+	}
 	if data[0] != '<' || (data[1] != 'h' && data[1] != 'H') || (data[2] != 'r' && data[2] != 'R') {
 		return 0
 	}
@@ -457,22 +451,31 @@ func (p *parser) htmlHr(out *bytes.Buffer, data []byte, doRender bool) int {
 		// not an <hr> tag after all; at least not a valid one
 		return 0
 	}
-
 	i := 3
-	for data[i] != '>' && data[i] != '\n' {
+	for i < len(data) && data[i] != '>' && data[i] != '\n' {
 		i++
 	}
-
-	if data[i] == '>' {
-		return p.renderHTMLBlock(out, data, i+1, doRender)
+	if i < len(data) && data[i] == '>' {
+		i++
+		if j := p.isEmpty(data[i:]); j > 0 {
+			size := i + j
+			if doRender {
+				// trim newlines
+				end := size
+				for end > 0 && data[end-1] == '\n' {
+					end--
+				}
+				finalizeHTMLBlock(p.addBlock(HTMLBlock, data[:end]))
+			}
+			return size
+		}
 	}
-
 	return 0
 }
 
-func (p *parser) htmlFindTag(data []byte) (string, bool) {
+func (p *Markdown) htmlFindTag(data []byte) (string, bool) {
 	i := 0
-	for isalnum(data[i]) {
+	for i < len(data) && isalnum(data[i]) {
 		i++
 	}
 	key := string(data[:i])
@@ -482,9 +485,11 @@ func (p *parser) htmlFindTag(data []byte) (string, bool) {
 	return "", false
 }
 
-func (p *parser) htmlFindEnd(tag string, data []byte) int {
+func (p *Markdown) htmlFindEnd(tag string, data []byte) int {
 	// assume data[0] == '<' && data[1] == '/' already tested
-
+	if tag == "hr" {
+		return 2
+	}
 	// check if tag is a match
 	closetag := []byte("</" + tag + ">")
 	if !bytes.HasPrefix(data, closetag) {
@@ -504,7 +509,7 @@ func (p *parser) htmlFindEnd(tag string, data []byte) int {
 		return i
 	}
 
-	if p.flags&EXTENSION_LAX_HTML_BLOCKS != 0 {
+	if p.extensions&LaxHTMLBlocks != 0 {
 		return i
 	}
 	if skip = p.isEmpty(data[i:]); skip == 0 {
@@ -515,7 +520,7 @@ func (p *parser) htmlFindEnd(tag string, data []byte) int {
 	return i + skip
 }
 
-func (p *parser) isEmpty(data []byte) int {
+func (*Markdown) isEmpty(data []byte) int {
 	// it is okay to call isEmpty on an empty buffer
 	if len(data) == 0 {
 		return 0
@@ -527,10 +532,13 @@ func (p *parser) isEmpty(data []byte) int {
 			return 0
 		}
 	}
-	return i + 1
+	if i < len(data) && data[i] == '\n' {
+		i++
+	}
+	return i
 }
 
-func (p *parser) isHRule(data []byte) bool {
+func (*Markdown) isHRule(data []byte) bool {
 	i := 0
 
 	// skip up to three spaces
@@ -546,7 +554,7 @@ func (p *parser) isHRule(data []byte) bool {
 
 	// the whole line must be the char or whitespace
 	n := 0
-	for data[i] != '\n' {
+	for i < len(data) && data[i] != '\n' {
 		switch {
 		case data[i] == c:
 			n++
@@ -559,21 +567,23 @@ func (p *parser) isHRule(data []byte) bool {
 	return n >= 3
 }
 
-func (p *parser) isFencedCode(data []byte, syntax **string, oldmarker string) (skip int, marker string) {
+// isFenceLine checks if there's a fence line (e.g., ``` or ``` go) at the beginning of data,
+// and returns the end index if so, or 0 otherwise. It also returns the marker found.
+// If info is not nil, it gets set to the syntax specified in the fence line.
+func isFenceLine(data []byte, info *string, oldmarker string) (end int, marker string) {
 	i, size := 0, 0
-	skip = 0
 
 	// skip up to three spaces
 	for i < len(data) && i < 3 && data[i] == ' ' {
 		i++
 	}
-	if i >= len(data) {
-		return
-	}
 
 	// check for the marker characters: ~ or `
+	if i >= len(data) {
+		return 0, ""
+	}
 	if data[i] != '~' && data[i] != '`' {
-		return
+		return 0, ""
 	}
 
 	c := data[i]
@@ -584,90 +594,95 @@ func (p *parser) isFencedCode(data []byte, syntax **string, oldmarker string) (s
 		i++
 	}
 
-	if i >= len(data) {
-		return
-	}
-
 	// the marker char must occur at least 3 times
 	if size < 3 {
-		return
+		return 0, ""
 	}
 	marker = string(data[i-size : i])
 
 	// if this is the end marker, it must match the beginning marker
 	if oldmarker != "" && marker != oldmarker {
-		return
+		return 0, ""
 	}
 
-	if syntax != nil {
-		syn := 0
+	// TODO(shurcooL): It's probably a good idea to simplify the 2 code paths here
+	// into one, always get the info string, and discard it if the caller doesn't care.
+	if info != nil {
+		infoLength := 0
 		i = skipChar(data, i, ' ')
 
 		if i >= len(data) {
-			return
+			if i == len(data) {
+				return i, marker
+			}
+			return 0, ""
 		}
 
-		syntaxStart := i
+		infoStart := i
 
 		if data[i] == '{' {
 			i++
-			syntaxStart++
+			infoStart++
 
 			for i < len(data) && data[i] != '}' && data[i] != '\n' {
-				syn++
+				infoLength++
 				i++
 			}
 
 			if i >= len(data) || data[i] != '}' {
-				return
+				return 0, ""
 			}
 
 			// strip all whitespace at the beginning and the end
 			// of the {} block
-			for syn > 0 && isspace(data[syntaxStart]) {
-				syntaxStart++
-				syn--
+			for infoLength > 0 && isspace(data[infoStart]) {
+				infoStart++
+				infoLength--
 			}
 
-			for syn > 0 && isspace(data[syntaxStart+syn-1]) {
-				syn--
+			for infoLength > 0 && isspace(data[infoStart+infoLength-1]) {
+				infoLength--
 			}
-
 			i++
+			i = skipChar(data, i, ' ')
 		} else {
-			for i < len(data) && !isspace(data[i]) {
-				syn++
+			for i < len(data) && !isverticalspace(data[i]) {
+				infoLength++
 				i++
 			}
 		}
 
-		language := string(data[syntaxStart : syntaxStart+syn])
-		*syntax = &language
+		*info = strings.TrimSpace(string(data[infoStart : infoStart+infoLength]))
 	}
 
-	i = skipChar(data, i, ' ')
-	if i >= len(data) || data[i] != '\n' {
-		return
+	if i == len(data) {
+		return i, marker
 	}
-
-	skip = i + 1
-	return
+	if i > len(data) || data[i] != '\n' {
+		return 0, ""
+	}
+	return i + 1, marker // Take newline into account.
 }
 
-func (p *parser) fencedCode(out *bytes.Buffer, data []byte, doRender bool) int {
-	var lang *string
-	beg, marker := p.isFencedCode(data, &lang, "")
+// fencedCodeBlock returns the end index if data contains a fenced code block at the beginning,
+// or 0 otherwise. It writes to out if doRender is true, otherwise it has no side effects.
+// If doRender is true, a final newline is mandatory to recognize the fenced code block.
+func (p *Markdown) fencedCodeBlock(data []byte, doRender bool) int {
+	var info string
+	beg, marker := isFenceLine(data, &info, "")
 	if beg == 0 || beg >= len(data) {
 		return 0
 	}
 
 	var work bytes.Buffer
+	work.Write([]byte(info))
+	work.WriteByte('\n')
 
 	for {
 		// safe to assume beg < len(data)
 
 		// check for the end of the code block
-		fenceEnd, _ := p.isFencedCode(data[beg:], nil, marker)
+		fenceEnd, _ := isFenceLine(data[beg:], nil, marker)
 		if fenceEnd != 0 {
 			beg += fenceEnd
 			break
@@ -688,30 +703,56 @@ func (p *parser) fencedCode(out *bytes.Buffer, data []byte, doRender bool) int {
 		beg = end
 	}
 
-	syntax := ""
-	if lang != nil {
-		syntax = *lang
-	}
-
 	if doRender {
-		p.r.BlockCode(out, work.Bytes(), syntax)
+		block := p.addBlock(CodeBlock, work.Bytes()) // TODO: get rid of temp buffer
+		block.IsFenced = true
+		finalizeCodeBlock(block)
 	}
 
 	return beg
 }
 
-func (p *parser) table(out *bytes.Buffer, data []byte) int {
-	var header bytes.Buffer
-	i, columns := p.tableHeader(&header, data)
+func unescapeChar(str []byte) []byte {
+	if str[0] == '\\' {
+		return []byte{str[1]}
+	}
+	return []byte(html.UnescapeString(string(str)))
+}
+
+func unescapeString(str []byte) []byte {
+	if reBackslashOrAmp.Match(str) {
+		return reEntityOrEscapedChar.ReplaceAllFunc(str, unescapeChar)
+	}
+	return str
+}
+
+func finalizeCodeBlock(block *Node) {
+	if block.IsFenced {
+		newlinePos := bytes.IndexByte(block.content, '\n')
+		firstLine := block.content[:newlinePos]
+		rest := block.content[newlinePos+1:]
+		block.Info = unescapeString(bytes.Trim(firstLine, "\n"))
+		block.Literal = rest
+	} else {
+		block.Literal = block.content
+	}
+	block.content = nil
+}
+
+func (p *Markdown) table(data []byte) int {
+	table := p.addBlock(Table, nil)
+	i, columns := p.tableHeader(data)
 	if i == 0 {
+		p.tip = table.Parent
+		table.Unlink()
 		return 0
 	}
 
-	var body bytes.Buffer
+	p.addBlock(TableBody, nil)
 
 	for i < len(data) {
 		pipes, rowStart := 0, i
-		for ; data[i] != '\n'; i++ {
+		for ; i < len(data) && data[i] != '\n'; i++ {
 			if data[i] == '|' {
 				pipes++
 			}
@@ -723,12 +764,12 @@ func (p *parser) table(out *bytes.Buffer, data []byte) int {
 		}
 
 		// include the newline in data sent to tableRow
-		i++
-		p.tableRow(&body, data[rowStart:i], columns, false)
+		if i < len(data) && data[i] == '\n' {
+			i++
+		}
+		p.tableRow(data[rowStart:i], columns, false)
 	}
 
-	p.r.Table(out, header.Bytes(), body.Bytes(), columns)
-
 	return i
 }
 
@@ -741,10 +782,10 @@ func isBackslashEscaped(data []byte, i int) bool {
 	return backslashes&1 == 1
 }
 
-func (p *parser) tableHeader(out *bytes.Buffer, data []byte) (size int, columns []int) {
+func (p *Markdown) tableHeader(data []byte) (size int, columns []CellAlignFlags) {
 	i := 0
 	colCount := 1
-	for i = 0; data[i] != '\n'; i++ {
+	for i = 0; i < len(data) && data[i] != '\n'; i++ {
 		if data[i] == '|' && !isBackslashEscaped(data, i) {
 			colCount++
 		}
@@ -756,7 +797,11 @@ func (p *parser) tableHeader(out *bytes.Buffer, data []byte) (size int, columns
 	}
 
 	// include the newline in the data sent to tableRow
-	header := data[:i+1]
+	j := i
+	if j < len(data) && data[j] == '\n' {
+		j++
+	}
+	header := data[:j]
 
 	// column count ignores pipes at beginning or end of line
 	if data[0] == '|' {
@@ -766,7 +811,7 @@ func (p *parser) tableHeader(out *bytes.Buffer, data []byte) (size int, columns
 		colCount--
 	}
 
-	columns = make([]int, colCount)
+	columns = make([]CellAlignFlags, colCount)
 
 	// move on to the header underline
 	i++
@@ -782,27 +827,29 @@ func (p *parser) tableHeader(out *bytes.Buffer, data []byte) (size int, columns
 	// each column header is of form: / *:?-+:? *|/ with # dashes + # colons >= 3
 	// and trailing | optional on last column
 	col := 0
-	for data[i] != '\n' {
+	for i < len(data) && data[i] != '\n' {
 		dashes := 0
 
 		if data[i] == ':' {
 			i++
-			columns[col] |= TABLE_ALIGNMENT_LEFT
+			columns[col] |= TableAlignmentLeft
 			dashes++
 		}
-		for data[i] == '-' {
+		for i < len(data) && data[i] == '-' {
 			i++
 			dashes++
 		}
-		if data[i] == ':' {
+		if i < len(data) && data[i] == ':' {
 			i++
-			columns[col] |= TABLE_ALIGNMENT_RIGHT
+			columns[col] |= TableAlignmentRight
 			dashes++
 		}
-		for data[i] == ' ' {
+		for i < len(data) && data[i] == ' ' {
 			i++
 		}
-
+		if i == len(data) {
+			return
+		}
 		// end of column test is messy
 		switch {
 		case dashes < 3:
@@ -813,12 +860,12 @@ func (p *parser) tableHeader(out *bytes.Buffer, data []byte) (size int, columns
 			// marker found, now skip past trailing whitespace
 			col++
 			i++
-			for data[i] == ' ' {
+			for i < len(data) && data[i] == ' ' {
 				i++
 			}
 
 			// trailing junk found after last column
-			if col >= colCount && data[i] != '\n' {
+			if col >= colCount && i < len(data) && data[i] != '\n' {
 				return
 			}
 
@@ -839,27 +886,31 @@ func (p *parser) tableHeader(out *bytes.Buffer, data []byte) (size int, columns
 		return
 	}
 
-	p.tableRow(out, header, columns, true)
-	size = i + 1
+	p.addBlock(TableHead, nil)
+	p.tableRow(header, columns, true)
+	size = i
+	if size < len(data) && data[size] == '\n' {
+		size++
+	}
 	return
 }
 
-func (p *parser) tableRow(out *bytes.Buffer, data []byte, columns []int, header bool) {
+func (p *Markdown) tableRow(data []byte, columns []CellAlignFlags, header bool) {
+	p.addBlock(TableRow, nil)
 	i, col := 0, 0
-	var rowWork bytes.Buffer
 
 	if data[i] == '|' && !isBackslashEscaped(data, i) {
 		i++
 	}
 
 	for col = 0; col < len(columns) && i < len(data); col++ {
-		for data[i] == ' ' {
+		for i < len(data) && data[i] == ' ' {
 			i++
 		}
 
 		cellStart := i
 
-		for (data[i] != '|' || isBackslashEscaped(data, i)) && data[i] != '\n' {
+		for i < len(data) && (data[i] != '|' || isBackslashEscaped(data, i)) && data[i] != '\n' {
 			i++
 		}
 
@@ -868,42 +919,33 @@ func (p *parser) tableRow(out *bytes.Buffer, data []byte, columns []int, header
 		// skip the end-of-cell marker, possibly taking us past end of buffer
 		i++
 
-		for cellEnd > cellStart && data[cellEnd-1] == ' ' {
+		for cellEnd > cellStart && cellEnd-1 < len(data) && data[cellEnd-1] == ' ' {
 			cellEnd--
 		}
 
-		var cellWork bytes.Buffer
-		p.inline(&cellWork, data[cellStart:cellEnd])
-
-		if header {
-			p.r.TableHeaderCell(&rowWork, cellWork.Bytes(), columns[col])
-		} else {
-			p.r.TableCell(&rowWork, cellWork.Bytes(), columns[col])
-		}
+		cell := p.addBlock(TableCell, data[cellStart:cellEnd])
+		cell.IsHeader = header
+		cell.Align = columns[col]
 	}
 
 	// pad it out with empty columns to get the right number
 	for ; col < len(columns); col++ {
-		if header {
-			p.r.TableHeaderCell(&rowWork, nil, columns[col])
-		} else {
-			p.r.TableCell(&rowWork, nil, columns[col])
-		}
+		cell := p.addBlock(TableCell, nil)
+		cell.IsHeader = header
+		cell.Align = columns[col]
 	}
 
 	// silently ignore rows with too many cells
-
-	p.r.TableRow(out, rowWork.Bytes())
 }
 
 // returns blockquote prefix length
-func (p *parser) quotePrefix(data []byte) int {
+func (p *Markdown) quotePrefix(data []byte) int {
 	i := 0
-	for i < 3 && data[i] == ' ' {
+	for i < 3 && i < len(data) && data[i] == ' ' {
 		i++
 	}
-	if data[i] == '>' {
-		if data[i+1] == ' ' {
+	if i < len(data) && data[i] == '>' {
+		if i+1 < len(data) && data[i+1] == ' ' {
 			return i + 2
 		}
 		return i + 1
@@ -913,7 +955,7 @@ func (p *parser) quotePrefix(data []byte) int {
 
 // blockquote ends with at least one blank line
 // followed by something without a blockquote prefix
-func (p *parser) terminateBlockquote(data []byte, beg, end int) bool {
+func (p *Markdown) terminateBlockquote(data []byte, beg, end int) bool {
 	if p.isEmpty(data[beg:]) <= 0 {
 		return false
 	}
@@ -924,7 +966,8 @@ func (p *parser) terminateBlockquote(data []byte, beg, end int) bool {
 }
 
 // parse a blockquote fragment
-func (p *parser) quote(out *bytes.Buffer, data []byte) int {
+func (p *Markdown) quote(data []byte) int {
+	block := p.addBlock(BlockQuote, nil)
 	var raw bytes.Buffer
 	beg, end := 0, 0
 	for beg < len(data) {
@@ -932,9 +975,9 @@ func (p *parser) quote(out *bytes.Buffer, data []byte) int {
 		// Step over whole lines, collecting them. While doing that, check for
 		// fenced code and if one's found, incorporate it altogether,
 		// irregardless of any contents inside it
-		for data[end] != '\n' {
-			if p.flags&EXTENSION_FENCED_CODE != 0 {
-				if i := p.fencedCode(out, data[end:], false); i > 0 {
+		for end < len(data) && data[end] != '\n' {
+			if p.extensions&FencedCode != 0 {
+				if i := p.fencedCodeBlock(data[end:], false); i > 0 {
 					// -1 to compensate for the extra end++ after the loop:
 					end += i - 1
 					break
@@ -942,44 +985,47 @@ func (p *parser) quote(out *bytes.Buffer, data []byte) int {
 			}
 			end++
 		}
-		end++
-
+		if end < len(data) && data[end] == '\n' {
+			end++
+		}
 		if pre := p.quotePrefix(data[beg:]); pre > 0 {
 			// skip the prefix
 			beg += pre
 		} else if p.terminateBlockquote(data, beg, end) {
 			break
 		}
-
 		// this line is part of the blockquote
 		raw.Write(data[beg:end])
 		beg = end
 	}
-
-	var cooked bytes.Buffer
-	p.block(&cooked, raw.Bytes())
-	p.r.BlockQuote(out, cooked.Bytes())
+	p.block(raw.Bytes())
+	p.finalize(block)
 	return end
 }
 
 // returns prefix length for block code
-func (p *parser) codePrefix(data []byte) int {
-	if data[0] == ' ' && data[1] == ' ' && data[2] == ' ' && data[3] == ' ' {
+func (p *Markdown) codePrefix(data []byte) int {
+	if len(data) >= 1 && data[0] == '\t' {
+		return 1
+	}
+	if len(data) >= 4 && data[0] == ' ' && data[1] == ' ' && data[2] == ' ' && data[3] == ' ' {
 		return 4
 	}
 	return 0
 }
 
-func (p *parser) code(out *bytes.Buffer, data []byte) int {
+func (p *Markdown) code(data []byte) int {
 	var work bytes.Buffer
 
 	i := 0
 	for i < len(data) {
 		beg := i
-		for data[i] != '\n' {
+		for i < len(data) && data[i] != '\n' {
+			i++
+		}
+		if i < len(data) && data[i] == '\n' {
 			i++
 		}
-		i++
 
 		blankline := p.isEmpty(data[beg:i]) > 0
 		if pre := p.codePrefix(data[beg:i]); pre > 0 {
@@ -990,7 +1036,7 @@ func (p *parser) code(out *bytes.Buffer, data []byte) int {
 			break
 		}
 
-		// verbatim copy to the working buffeu
+		// verbatim copy to the working buffer
 		if blankline {
 			work.WriteByte('\n')
 		} else {
@@ -1010,122 +1056,195 @@ func (p *parser) code(out *bytes.Buffer, data []byte) int {
 
 	work.WriteByte('\n')
 
-	p.r.BlockCode(out, work.Bytes(), "")
+	block := p.addBlock(CodeBlock, work.Bytes()) // TODO: get rid of temp buffer
+	block.IsFenced = false
+	finalizeCodeBlock(block)
 
 	return i
 }
 
 // returns unordered list item prefix
-func (p *parser) uliPrefix(data []byte) int {
+func (p *Markdown) uliPrefix(data []byte) int {
 	i := 0
-
 	// start with up to 3 spaces
-	for i < 3 && data[i] == ' ' {
+	for i < len(data) && i < 3 && data[i] == ' ' {
 		i++
 	}
-
-	// need a *, +, or - followed by a space
+	if i >= len(data)-1 {
+		return 0
+	}
+	// need one of {'*', '+', '-'} followed by a space or a tab
 	if (data[i] != '*' && data[i] != '+' && data[i] != '-') ||
-		data[i+1] != ' ' {
+		(data[i+1] != ' ' && data[i+1] != '\t') {
 		return 0
 	}
 	return i + 2
 }
 
 // returns ordered list item prefix
-func (p *parser) oliPrefix(data []byte) int {
+func (p *Markdown) oliPrefix(data []byte) int {
 	i := 0
 
 	// start with up to 3 spaces
-	for i < 3 && data[i] == ' ' {
+	for i < 3 && i < len(data) && data[i] == ' ' {
 		i++
 	}
 
 	// count the digits
 	start := i
-	for data[i] >= '0' && data[i] <= '9' {
+	for i < len(data) && data[i] >= '0' && data[i] <= '9' {
 		i++
 	}
+	if start == i || i >= len(data)-1 {
+		return 0
+	}
 
-	// we need >= 1 digits followed by a dot and a space
-	if start == i || data[i] != '.' || data[i+1] != ' ' {
+	// we need >= 1 digits followed by a dot and a space or a tab
+	if data[i] != '.' || !(data[i+1] == ' ' || data[i+1] == '\t') {
 		return 0
 	}
 	return i + 2
 }
 
 // returns definition list item prefix
-func (p *parser) dliPrefix(data []byte) int {
-	i := 0
-
-	// need a : followed by a spaces
-	if data[i] != ':' || data[i+1] != ' ' {
+func (p *Markdown) dliPrefix(data []byte) int {
+	if len(data) < 2 {
 		return 0
 	}
-	for data[i] == ' ' {
+	i := 0
+	// need a ':' followed by a space or a tab
+	if data[i] != ':' || !(data[i+1] == ' ' || data[i+1] == '\t') {
+		return 0
+	}
+	for i < len(data) && data[i] == ' ' {
 		i++
 	}
 	return i + 2
 }
 
 // parse ordered or unordered list block
-func (p *parser) list(out *bytes.Buffer, data []byte, flags int) int {
+func (p *Markdown) list(data []byte, flags ListType) int {
 	i := 0
-	flags |= LIST_ITEM_BEGINNING_OF_LIST
-	work := func() bool {
-		for i < len(data) {
-			skip := p.listItem(out, data[i:], &flags)
-			i += skip
+	flags |= ListItemBeginningOfList
+	block := p.addBlock(List, nil)
+	block.ListFlags = flags
+	block.Tight = true
 
-			if skip == 0 || flags&LIST_ITEM_END_OF_LIST != 0 {
-				break
-			}
-			flags &= ^LIST_ITEM_BEGINNING_OF_LIST
+	for i < len(data) {
+		skip := p.listItem(data[i:], &flags)
+		if flags&ListItemContainsBlock != 0 {
+			block.ListData.Tight = false
 		}
-		return true
+		i += skip
+		if skip == 0 || flags&ListItemEndOfList != 0 {
+			break
+		}
+		flags &= ^ListItemBeginningOfList
 	}
 
-	p.r.List(out, work, flags)
+	above := block.Parent
+	finalizeList(block)
+	p.tip = above
 	return i
 }
 
+// Returns true if the list item is not the same type as its parent list
+func (p *Markdown) listTypeChanged(data []byte, flags *ListType) bool {
+	if p.dliPrefix(data) > 0 && *flags&ListTypeDefinition == 0 {
+		return true
+	} else if p.oliPrefix(data) > 0 && *flags&ListTypeOrdered == 0 {
+		return true
+	} else if p.uliPrefix(data) > 0 && (*flags&ListTypeOrdered != 0 || *flags&ListTypeDefinition != 0) {
+		return true
+	}
+	return false
+}
+
+// Returns true if block ends with a blank line, descending if needed
+// into lists and sublists.
+func endsWithBlankLine(block *Node) bool {
+	// TODO: figure this out. Always false now.
+	for block != nil {
+		//if block.lastLineBlank {
+		//return true
+		//}
+		t := block.Type
+		if t == List || t == Item {
+			block = block.LastChild
+		} else {
+			break
+		}
+	}
+	return false
+}
+
+func finalizeList(block *Node) {
+	block.open = false
+	item := block.FirstChild
+	for item != nil {
+		// check for non-final list item ending with blank line:
+		if endsWithBlankLine(item) && item.Next != nil {
+			block.ListData.Tight = false
+			break
+		}
+		// recurse into children of list item, to see if there are spaces
+		// between any of them:
+		subItem := item.FirstChild
+		for subItem != nil {
+			if endsWithBlankLine(subItem) && (item.Next != nil || subItem.Next != nil) {
+				block.ListData.Tight = false
+				break
+			}
+			subItem = subItem.Next
+		}
+		item = item.Next
+	}
+}
+
 // Parse a single list item.
 // Assumes initial prefix is already removed if this is a sublist.
-func (p *parser) listItem(out *bytes.Buffer, data []byte, flags *int) int {
+func (p *Markdown) listItem(data []byte, flags *ListType) int {
 	// keep track of the indentation of the first line
 	itemIndent := 0
-	for itemIndent < 3 && data[itemIndent] == ' ' {
-		itemIndent++
+	if data[0] == '\t' {
+		itemIndent += 4
+	} else {
+		for itemIndent < 3 && data[itemIndent] == ' ' {
+			itemIndent++
+		}
 	}
 
+	var bulletChar byte = '*'
 	i := p.uliPrefix(data)
 	if i == 0 {
 		i = p.oliPrefix(data)
+	} else {
+		bulletChar = data[i-2]
 	}
 	if i == 0 {
 		i = p.dliPrefix(data)
 		// reset definition term flag
 		if i > 0 {
-			*flags &= ^LIST_TYPE_TERM
+			*flags &= ^ListTypeTerm
 		}
 	}
 	if i == 0 {
-		// if in defnition list, set term flag and continue
-		if *flags&LIST_TYPE_DEFINITION != 0 {
-			*flags |= LIST_TYPE_TERM
+		// if in definition list, set term flag and continue
+		if *flags&ListTypeDefinition != 0 {
+			*flags |= ListTypeTerm
 		} else {
 			return 0
 		}
 	}
 
 	// skip leading whitespace on first line
-	for data[i] == ' ' {
+	for i < len(data) && data[i] == ' ' {
 		i++
 	}
 
 	// find the end of the line
 	line := i
-	for i > 0 && data[i-1] != '\n' {
+	for i > 0 && i < len(data) && data[i-1] != '\n' {
 		i++
 	}
 
@@ -1139,13 +1258,14 @@ func (p *parser) listItem(out *bytes.Buffer, data []byte, flags *int) int {
 	// process the following lines
 	containsBlankLine := false
 	sublist := 0
+	codeBlockMarker := ""
 
 gatherlines:
 	for line < len(data) {
 		i++
 
 		// find the end of this line
-		for data[i-1] != '\n' {
+		for i < len(data) && data[i-1] != '\n' {
 			i++
 		}
 
@@ -1153,18 +1273,45 @@ gatherlines:
 		// and move on to the next line
 		if p.isEmpty(data[line:i]) > 0 {
 			containsBlankLine = true
-			raw.Write(data[line:i])
 			line = i
 			continue
 		}
 
 		// calculate the indentation
 		indent := 0
-		for indent < 4 && line+indent < i && data[line+indent] == ' ' {
-			indent++
+		indentIndex := 0
+		if data[line] == '\t' {
+			indentIndex++
+			indent += 4
+		} else {
+			for indent < 4 && line+indent < i && data[line+indent] == ' ' {
+				indent++
+				indentIndex++
+			}
 		}
 
-		chunk := data[line+indent : i]
+		chunk := data[line+indentIndex : i]
+
+		if p.extensions&FencedCode != 0 {
+			// determine if in or out of codeblock
+			// if in codeblock, ignore normal list processing
+			_, marker := isFenceLine(chunk, nil, codeBlockMarker)
+			if marker != "" {
+				if codeBlockMarker == "" {
+					// start of codeblock
+					codeBlockMarker = marker
+				} else {
+					// end of codeblock.
+					codeBlockMarker = ""
+				}
+			}
+			// we are in a codeblock, write line, and continue
+			if codeBlockMarker != "" || marker != "" {
+				raw.Write(data[line+indentIndex : i])
+				line = i
+				continue gatherlines
+			}
+		}
 
 		// evaluate how this line fits in
 		switch {
@@ -1173,22 +1320,21 @@ gatherlines:
 			p.oliPrefix(chunk) > 0 ||
 			p.dliPrefix(chunk) > 0:
 
-			if containsBlankLine {
-				// end the list if the type changed after a blank line
-				if indent <= itemIndent &&
-					((*flags&LIST_TYPE_ORDERED != 0 && p.uliPrefix(chunk) > 0) ||
-						(*flags&LIST_TYPE_ORDERED == 0 && p.oliPrefix(chunk) > 0)) {
-
-					*flags |= LIST_ITEM_END_OF_LIST
-					break gatherlines
+			// to be a nested list, it must be indented more
+			// if not, it is either a different kind of list
+			// or the next item in the same list
+			if indent <= itemIndent {
+				if p.listTypeChanged(chunk, flags) {
+					*flags |= ListItemEndOfList
+				} else if containsBlankLine {
+					*flags |= ListItemContainsBlock
 				}
-				*flags |= LIST_ITEM_CONTAINS_BLOCK
+
+				break gatherlines
 			}
 
-			// to be a nested list, it must be indented more
-			// if not, it is the next item in the same list
-			if indent <= itemIndent {
-				break gatherlines
+			if containsBlankLine {
+				*flags |= ListItemContainsBlock
 			}
 
 			// is this the first item in the nested list?
@@ -1196,87 +1342,89 @@ gatherlines:
 				sublist = raw.Len()
 			}
 
-		// is this a nested prefix header?
-		case p.isPrefixHeader(chunk):
-			// if the header is not indented, it is not nested in the list
+		// is this a nested prefix heading?
+		case p.isPrefixHeading(chunk):
+			// if the heading is not indented, it is not nested in the list
 			// and thus ends the list
 			if containsBlankLine && indent < 4 {
-				*flags |= LIST_ITEM_END_OF_LIST
+				*flags |= ListItemEndOfList
 				break gatherlines
 			}
-			*flags |= LIST_ITEM_CONTAINS_BLOCK
+			*flags |= ListItemContainsBlock
 
 		// anything following an empty line is only part
 		// of this item if it is indented 4 spaces
 		// (regardless of the indentation of the beginning of the item)
 		case containsBlankLine && indent < 4:
-			if *flags&LIST_TYPE_DEFINITION != 0 && i < len(data)-1 {
+			if *flags&ListTypeDefinition != 0 && i < len(data)-1 {
 				// is the next item still a part of this list?
 				next := i
-				for data[next] != '\n' {
+				for next < len(data) && data[next] != '\n' {
 					next++
 				}
 				for next < len(data)-1 && data[next] == '\n' {
 					next++
 				}
 				if i < len(data)-1 && data[i] != ':' && data[next] != ':' {
-					*flags |= LIST_ITEM_END_OF_LIST
+					*flags |= ListItemEndOfList
 				}
 			} else {
-				*flags |= LIST_ITEM_END_OF_LIST
+				*flags |= ListItemEndOfList
 			}
 			break gatherlines
 
 		// a blank line means this should be parsed as a block
 		case containsBlankLine:
-			*flags |= LIST_ITEM_CONTAINS_BLOCK
+			raw.WriteByte('\n')
+			*flags |= ListItemContainsBlock
 		}
 
-		containsBlankLine = false
+		// if this line was preceded by one or more blanks,
+		// re-introduce the blank into the buffer
+		if containsBlankLine {
+			containsBlankLine = false
+			raw.WriteByte('\n')
+		}
 
 		// add the line into the working buffer without prefix
-		raw.Write(data[line+indent : i])
+		raw.Write(data[line+indentIndex : i])
 
 		line = i
 	}
 
 	rawBytes := raw.Bytes()
 
+	block := p.addBlock(Item, nil)
+	block.ListFlags = *flags
+	block.Tight = false
+	block.BulletChar = bulletChar
+	block.Delimiter = '.' // Only '.' is possible in Markdown, but ')' will also be possible in CommonMark
+
 	// render the contents of the list item
-	var cooked bytes.Buffer
-	if *flags&LIST_ITEM_CONTAINS_BLOCK != 0 && *flags&LIST_TYPE_TERM == 0 {
+	if *flags&ListItemContainsBlock != 0 && *flags&ListTypeTerm == 0 {
 		// intermediate render of block item, except for definition term
 		if sublist > 0 {
-			p.block(&cooked, rawBytes[:sublist])
-			p.block(&cooked, rawBytes[sublist:])
+			p.block(rawBytes[:sublist])
+			p.block(rawBytes[sublist:])
 		} else {
-			p.block(&cooked, rawBytes)
+			p.block(rawBytes)
 		}
 	} else {
 		// intermediate render of inline item
 		if sublist > 0 {
-			p.inline(&cooked, rawBytes[:sublist])
-			p.block(&cooked, rawBytes[sublist:])
+			child := p.addChild(Paragraph, 0)
+			child.content = rawBytes[:sublist]
+			p.block(rawBytes[sublist:])
 		} else {
-			p.inline(&cooked, rawBytes)
+			child := p.addChild(Paragraph, 0)
+			child.content = rawBytes
 		}
 	}
-
-	// render the actual list item
-	cookedBytes := cooked.Bytes()
-	parsedEnd := len(cookedBytes)
-
-	// strip trailing newlines
-	for parsedEnd > 0 && cookedBytes[parsedEnd-1] == '\n' {
-		parsedEnd--
-	}
-	p.r.ListItem(out, cookedBytes[:parsedEnd], *flags)
-
 	return line
 }
 
 // render a single paragraph that has already been parsed out
-func (p *parser) renderParagraph(out *bytes.Buffer, data []byte) {
+func (p *Markdown) renderParagraph(data []byte) {
 	if len(data) == 0 {
 		return
 	}
@@ -1287,27 +1435,29 @@ func (p *parser) renderParagraph(out *bytes.Buffer, data []byte) {
 		beg++
 	}
 
+	end := len(data)
 	// trim trailing newline
-	end := len(data) - 1
+	if data[len(data)-1] == '\n' {
+		end--
+	}
 
 	// trim trailing spaces
 	for end > beg && data[end-1] == ' ' {
 		end--
 	}
 
-	work := func() bool {
-		p.inline(out, data[beg:end])
-		return true
-	}
-	p.r.Paragraph(out, work)
+	p.addBlock(Paragraph, data[beg:end])
 }
 
-func (p *parser) paragraph(out *bytes.Buffer, data []byte) int {
+func (p *Markdown) paragraph(data []byte) int {
 	// prev: index of 1st char of previous line
 	// line: index of 1st char of current line
 	// i: index of cursor/end of current line
 	var prev, line, i int
-
+	tabSize := TabSizeDefault
+	if p.extensions&TabSizeEight != 0 {
+		tabSize = TabSizeDouble
+	}
 	// keep going until we find something to mark the end of the paragraph
 	for i < len(data) {
 		// mark the beginning of the current line
@@ -1315,24 +1465,32 @@ func (p *parser) paragraph(out *bytes.Buffer, data []byte) int {
 		current := data[i:]
 		line = i
 
+		// did we find a reference or a footnote? If so, end a paragraph
+		// preceding it and report that we have consumed up to the end of that
+		// reference:
+		if refEnd := isReference(p, current, tabSize); refEnd > 0 {
+			p.renderParagraph(data[:i])
+			return i + refEnd
+		}
+
 		// did we find a blank line marking the end of the paragraph?
 		if n := p.isEmpty(current); n > 0 {
 			// did this blank line followed by a definition list item?
-			if p.flags&EXTENSION_DEFINITION_LISTS != 0 {
+			if p.extensions&DefinitionLists != 0 {
 				if i < len(data)-1 && data[i+1] == ':' {
-					return p.list(out, data[prev:], LIST_TYPE_DEFINITION)
+					return p.list(data[prev:], ListTypeDefinition)
 				}
 			}
 
-			p.renderParagraph(out, data[:i])
+			p.renderParagraph(data[:i])
 			return i + n
 		}
 
-		// an underline under some text marks a header, so our paragraph ended on prev line
+		// an underline under some text marks a heading, so our paragraph ended on prev line
 		if i > 0 {
-			if level := p.isUnderlinedHeader(current); level > 0 {
+			if level := p.isUnderlinedHeading(current); level > 0 {
 				// render the paragraph
-				p.renderParagraph(out, data[:prev])
+				p.renderParagraph(data[:prev])
 
 				// ignore leading and trailing whitespace
 				eol := i - 1
@@ -1343,24 +1501,17 @@ func (p *parser) paragraph(out *bytes.Buffer, data []byte) int {
 					eol--
 				}
 
-				// render the header
-				// this ugly double closure avoids forcing variables onto the heap
-				work := func(o *bytes.Buffer, pp *parser, d []byte) func() bool {
-					return func() bool {
-						pp.inline(o, d)
-						return true
-					}
-				}(out, p, data[prev:eol])
-
 				id := ""
-				if p.flags&EXTENSION_AUTO_HEADER_IDS != 0 {
+				if p.extensions&AutoHeadingIDs != 0 {
 					id = sanitized_anchor_name.Create(string(data[prev:eol]))
 				}
 
-				p.r.Header(out, work, level, id)
+				block := p.addBlock(Heading, data[prev:eol])
+				block.Level = level
+				block.HeadingID = id
 
 				// find the end of the underline
-				for data[i] != '\n' {
+				for i < len(data) && data[i] != '\n' {
 					i++
 				}
 				return i
@@ -1368,53 +1519,72 @@ func (p *parser) paragraph(out *bytes.Buffer, data []byte) int {
 		}
 
 		// if the next line starts a block of HTML, then the paragraph ends here
-		if p.flags&EXTENSION_LAX_HTML_BLOCKS != 0 {
-			if data[i] == '<' && p.html(out, current, false) > 0 {
+		if p.extensions&LaxHTMLBlocks != 0 {
+			if data[i] == '<' && p.html(current, false) > 0 {
 				// rewind to before the HTML block
-				p.renderParagraph(out, data[:i])
+				p.renderParagraph(data[:i])
 				return i
 			}
 		}
 
-		// if there's a prefixed header or a horizontal rule after this, paragraph is over
-		if p.isPrefixHeader(current) || p.isHRule(current) {
-			p.renderParagraph(out, data[:i])
+		// if there's a prefixed heading or a horizontal rule after this, paragraph is over
+		if p.isPrefixHeading(current) || p.isHRule(current) {
+			p.renderParagraph(data[:i])
 			return i
 		}
 
 		// if there's a fenced code block, paragraph is over
-		if p.flags&EXTENSION_FENCED_CODE != 0 {
-			if p.fencedCode(out, current, false) > 0 {
-				p.renderParagraph(out, data[:i])
+		if p.extensions&FencedCode != 0 {
+			if p.fencedCodeBlock(current, false) > 0 {
+				p.renderParagraph(data[:i])
 				return i
 			}
 		}
 
 		// if there's a definition list item, prev line is a definition term
-		if p.flags&EXTENSION_DEFINITION_LISTS != 0 {
+		if p.extensions&DefinitionLists != 0 {
 			if p.dliPrefix(current) != 0 {
-				return p.list(out, data[prev:], LIST_TYPE_DEFINITION)
+				ret := p.list(data[prev:], ListTypeDefinition)
+				return ret
 			}
 		}
 
 		// if there's a list after this, paragraph is over
-		if p.flags&EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK != 0 {
+		if p.extensions&NoEmptyLineBeforeBlock != 0 {
 			if p.uliPrefix(current) != 0 ||
 				p.oliPrefix(current) != 0 ||
 				p.quotePrefix(current) != 0 ||
 				p.codePrefix(current) != 0 {
-				p.renderParagraph(out, data[:i])
+				p.renderParagraph(data[:i])
 				return i
 			}
 		}
 
 		// otherwise, scan to the beginning of the next line
-		for data[i] != '\n' {
-			i++
+		nl := bytes.IndexByte(data[i:], '\n')
+		if nl >= 0 {
+			i += nl + 1
+		} else {
+			i += len(data[i:])
 		}
-		i++
 	}
 
-	p.renderParagraph(out, data[:i])
+	p.renderParagraph(data[:i])
+	return i
+}
+
+func skipChar(data []byte, start int, char byte) int {
+	i := start
+	for i < len(data) && data[i] == char {
+		i++
+	}
+	return i
+}
+
+func skipUntilChar(text []byte, start int, char byte) int {
+	i := start
+	for i < len(text) && text[i] != char {
+		i++
+	}
 	return i
 }
diff --git a/vendor/github.com/russross/blackfriday/v2/doc.go b/vendor/github.com/russross/blackfriday/v2/doc.go
new file mode 100644
index 0000000000..5b3fa9876a
--- /dev/null
+++ b/vendor/github.com/russross/blackfriday/v2/doc.go
@@ -0,0 +1,18 @@
+// Package blackfriday is a markdown processor.
+//
+// It translates plain text with simple formatting rules into an AST, which can
+// then be further processed to HTML (provided by Blackfriday itself) or other
+// formats (provided by the community).
+//
+// The simplest way to invoke Blackfriday is to call the Run function. It will
+// take a text input and produce a text output in HTML (or other format).
+//
+// A slightly more sophisticated way to use Blackfriday is to create a Markdown
+// processor and to call Parse, which returns a syntax tree for the input
+// document. You can leverage Blackfriday's parsing for content extraction from
+// markdown documents. You can assign a custom renderer and set various options
+// to the Markdown processor.
+//
+// If you're interested in calling Blackfriday from command line, see
+// https://github.com/russross/blackfriday-tool.
+package blackfriday
diff --git a/vendor/github.com/russross/blackfriday/v2/esc.go b/vendor/github.com/russross/blackfriday/v2/esc.go
new file mode 100644
index 0000000000..6385f27cb6
--- /dev/null
+++ b/vendor/github.com/russross/blackfriday/v2/esc.go
@@ -0,0 +1,34 @@
+package blackfriday
+
+import (
+	"html"
+	"io"
+)
+
+var htmlEscaper = [256][]byte{
+	'&': []byte("&amp;"),
+	'<': []byte("&lt;"),
+	'>': []byte("&gt;"),
+	'"': []byte("&quot;"),
+}
+
+func escapeHTML(w io.Writer, s []byte) {
+	var start, end int
+	for end < len(s) {
+		escSeq := htmlEscaper[s[end]]
+		if escSeq != nil {
+			w.Write(s[start:end])
+			w.Write(escSeq)
+			start = end + 1
+		}
+		end++
+	}
+	if start < len(s) && end <= len(s) {
+		w.Write(s[start:end])
+	}
+}
+
+func escLink(w io.Writer, text []byte) {
+	unesc := html.UnescapeString(string(text))
+	escapeHTML(w, []byte(unesc))
+}
diff --git a/vendor/github.com/russross/blackfriday/v2/go.mod b/vendor/github.com/russross/blackfriday/v2/go.mod
new file mode 100644
index 0000000000..620b74e0ac
--- /dev/null
+++ b/vendor/github.com/russross/blackfriday/v2/go.mod
@@ -0,0 +1 @@
+module github.com/russross/blackfriday/v2
diff --git a/vendor/github.com/russross/blackfriday/v2/html.go b/vendor/github.com/russross/blackfriday/v2/html.go
new file mode 100644
index 0000000000..284c87184f
--- /dev/null
+++ b/vendor/github.com/russross/blackfriday/v2/html.go
@@ -0,0 +1,949 @@
+//
+// Blackfriday Markdown Processor
+// Available at http://github.com/russross/blackfriday
+//
+// Copyright © 2011 Russ Ross <russ@russross.com>.
+// Distributed under the Simplified BSD License.
+// See README.md for details.
+//
+
+//
+//
+// HTML rendering backend
+//
+//
+
+package blackfriday
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"regexp"
+	"strings"
+)
+
+// HTMLFlags control optional behavior of HTML renderer.
+type HTMLFlags int
+
+// HTML renderer configuration options.
+const (
+	HTMLFlagsNone           HTMLFlags = 0
+	SkipHTML                HTMLFlags = 1 << iota // Skip preformatted HTML blocks
+	SkipImages                                    // Skip embedded images
+	SkipLinks                                     // Skip all links
+	Safelink                                      // Only link to trusted protocols
+	NofollowLinks                                 // Only link with rel="nofollow"
+	NoreferrerLinks                               // Only link with rel="noreferrer"
+	NoopenerLinks                                 // Only link with rel="noopener"
+	HrefTargetBlank                               // Add a blank target
+	CompletePage                                  // Generate a complete HTML page
+	UseXHTML                                      // Generate XHTML output instead of HTML
+	FootnoteReturnLinks                           // Generate a link at the end of a footnote to return to the source
+	Smartypants                                   // Enable smart punctuation substitutions
+	SmartypantsFractions                          // Enable smart fractions (with Smartypants)
+	SmartypantsDashes                             // Enable smart dashes (with Smartypants)
+	SmartypantsLatexDashes                        // Enable LaTeX-style dashes (with Smartypants)
+	SmartypantsAngledQuotes                       // Enable angled double quotes (with Smartypants) for double quotes rendering
+	SmartypantsQuotesNBSP                         // Enable « French guillemets » (with Smartypants)
+	TOC                                           // Generate a table of contents
+)
+
+var (
+	htmlTagRe = regexp.MustCompile("(?i)^" + htmlTag)
+)
+
+const (
+	htmlTag = "(?:" + openTag + "|" + closeTag + "|" + htmlComment + "|" +
+		processingInstruction + "|" + declaration + "|" + cdata + ")"
+	closeTag              = "</" + tagName + "\\s*[>]"
+	openTag               = "<" + tagName + attribute + "*" + "\\s*/?>"
+	attribute             = "(?:" + "\\s+" + attributeName + attributeValueSpec + "?)"
+	attributeValue        = "(?:" + unquotedValue + "|" + singleQuotedValue + "|" + doubleQuotedValue + ")"
+	attributeValueSpec    = "(?:" + "\\s*=" + "\\s*" + attributeValue + ")"
+	attributeName         = "[a-zA-Z_:][a-zA-Z0-9:._-]*"
+	cdata                 = "<!\\[CDATA\\[[\\s\\S]*?\\]\\]>"
+	declaration           = "<![A-Z]+" + "\\s+[^>]*>"
+	doubleQuotedValue     = "\"[^\"]*\""
+	htmlComment           = "<!---->|<!--(?:-?[^>-])(?:-?[^-])*-->"
+	processingInstruction = "[<][?].*?[?][>]"
+	singleQuotedValue     = "'[^']*'"
+	tagName               = "[A-Za-z][A-Za-z0-9-]*"
+	unquotedValue         = "[^\"'=<>`\\x00-\\x20]+"
+)
+
+// HTMLRendererParameters is a collection of supplementary parameters tweaking
+// the behavior of various parts of HTML renderer.
+type HTMLRendererParameters struct {
+	// Prepend this text to each relative URL.
+	AbsolutePrefix string
+	// Add this text to each footnote anchor, to ensure uniqueness.
+	FootnoteAnchorPrefix string
+	// Show this text inside the <a> tag for a footnote return link, if the
+	// HTML_FOOTNOTE_RETURN_LINKS flag is enabled. If blank, the string
+	// <sup>[return]</sup> is used.
+	FootnoteReturnLinkContents string
+	// If set, add this text to the front of each Heading ID, to ensure
+	// uniqueness.
+	HeadingIDPrefix string
+	// If set, add this text to the back of each Heading ID, to ensure uniqueness.
+	HeadingIDSuffix string
+	// Increase heading levels: if the offset is 1, <h1> becomes <h2> etc.
+	// Negative offset is also valid.
+	// Resulting levels are clipped between 1 and 6.
+	HeadingLevelOffset int
+
+	Title string // Document title (used if CompletePage is set)
+	CSS   string // Optional CSS file URL (used if CompletePage is set)
+	Icon  string // Optional icon file URL (used if CompletePage is set)
+
+	Flags HTMLFlags // Flags allow customizing this renderer's behavior
+}
+
+// HTMLRenderer is a type that implements the Renderer interface for HTML output.
+//
+// Do not create this directly, instead use the NewHTMLRenderer function.
+type HTMLRenderer struct {
+	HTMLRendererParameters
+
+	closeTag string // how to end singleton tags: either " />" or ">"
+
+	// Track heading IDs to prevent ID collision in a single generation.
+	headingIDs map[string]int
+
+	lastOutputLen int
+	disableTags   int
+
+	sr *SPRenderer
+}
+
+const (
+	xhtmlClose = " />"
+	htmlClose  = ">"
+)
+
+// NewHTMLRenderer creates and configures an HTMLRenderer object, which
+// satisfies the Renderer interface.
+func NewHTMLRenderer(params HTMLRendererParameters) *HTMLRenderer {
+	// configure the rendering engine
+	closeTag := htmlClose
+	if params.Flags&UseXHTML != 0 {
+		closeTag = xhtmlClose
+	}
+
+	if params.FootnoteReturnLinkContents == "" {
+		params.FootnoteReturnLinkContents = `<sup>[return]</sup>`
+	}
+
+	return &HTMLRenderer{
+		HTMLRendererParameters: params,
+
+		closeTag:   closeTag,
+		headingIDs: make(map[string]int),
+
+		sr: NewSmartypantsRenderer(params.Flags),
+	}
+}
+
+func isHTMLTag(tag []byte, tagname string) bool {
+	found, _ := findHTMLTagPos(tag, tagname)
+	return found
+}
+
+// Look for a character, but ignore it when it's in any kind of quotes, it
+// might be JavaScript
+func skipUntilCharIgnoreQuotes(html []byte, start int, char byte) int {
+	inSingleQuote := false
+	inDoubleQuote := false
+	inGraveQuote := false
+	i := start
+	for i < len(html) {
+		switch {
+		case html[i] == char && !inSingleQuote && !inDoubleQuote && !inGraveQuote:
+			return i
+		case html[i] == '\'':
+			inSingleQuote = !inSingleQuote
+		case html[i] == '"':
+			inDoubleQuote = !inDoubleQuote
+		case html[i] == '`':
+			inGraveQuote = !inGraveQuote
+		}
+		i++
+	}
+	return start
+}
+
+func findHTMLTagPos(tag []byte, tagname string) (bool, int) {
+	i := 0
+	if i < len(tag) && tag[0] != '<' {
+		return false, -1
+	}
+	i++
+	i = skipSpace(tag, i)
+
+	if i < len(tag) && tag[i] == '/' {
+		i++
+	}
+
+	i = skipSpace(tag, i)
+	j := 0
+	for ; i < len(tag); i, j = i+1, j+1 {
+		if j >= len(tagname) {
+			break
+		}
+
+		if strings.ToLower(string(tag[i]))[0] != tagname[j] {
+			return false, -1
+		}
+	}
+
+	if i == len(tag) {
+		return false, -1
+	}
+
+	rightAngle := skipUntilCharIgnoreQuotes(tag, i, '>')
+	if rightAngle >= i {
+		return true, rightAngle
+	}
+
+	return false, -1
+}
+
+func skipSpace(tag []byte, i int) int {
+	for i < len(tag) && isspace(tag[i]) {
+		i++
+	}
+	return i
+}
+
+func isRelativeLink(link []byte) (yes bool) {
+	// a tag begin with '#'
+	if link[0] == '#' {
+		return true
+	}
+
+	// link begin with '/' but not '//', the second maybe a protocol relative link
+	if len(link) >= 2 && link[0] == '/' && link[1] != '/' {
+		return true
+	}
+
+	// only the root '/'
+	if len(link) == 1 && link[0] == '/' {
+		return true
+	}
+
+	// current directory : begin with "./"
+	if bytes.HasPrefix(link, []byte("./")) {
+		return true
+	}
+
+	// parent directory : begin with "../"
+	if bytes.HasPrefix(link, []byte("../")) {
+		return true
+	}
+
+	return false
+}
+
+func (r *HTMLRenderer) ensureUniqueHeadingID(id string) string {
+	for count, found := r.headingIDs[id]; found; count, found = r.headingIDs[id] {
+		tmp := fmt.Sprintf("%s-%d", id, count+1)
+
+		if _, tmpFound := r.headingIDs[tmp]; !tmpFound {
+			r.headingIDs[id] = count + 1
+			id = tmp
+		} else {
+			id = id + "-1"
+		}
+	}
+
+	if _, found := r.headingIDs[id]; !found {
+		r.headingIDs[id] = 0
+	}
+
+	return id
+}
+
+func (r *HTMLRenderer) addAbsPrefix(link []byte) []byte {
+	if r.AbsolutePrefix != "" && isRelativeLink(link) && link[0] != '.' {
+		newDest := r.AbsolutePrefix
+		if link[0] != '/' {
+			newDest += "/"
+		}
+		newDest += string(link)
+		return []byte(newDest)
+	}
+	return link
+}
+
+func appendLinkAttrs(attrs []string, flags HTMLFlags, link []byte) []string {
+	if isRelativeLink(link) {
+		return attrs
+	}
+	val := []string{}
+	if flags&NofollowLinks != 0 {
+		val = append(val, "nofollow")
+	}
+	if flags&NoreferrerLinks != 0 {
+		val = append(val, "noreferrer")
+	}
+	if flags&NoopenerLinks != 0 {
+		val = append(val, "noopener")
+	}
+	if flags&HrefTargetBlank != 0 {
+		attrs = append(attrs, "target=\"_blank\"")
+	}
+	if len(val) == 0 {
+		return attrs
+	}
+	attr := fmt.Sprintf("rel=%q", strings.Join(val, " "))
+	return append(attrs, attr)
+}
+
+func isMailto(link []byte) bool {
+	return bytes.HasPrefix(link, []byte("mailto:"))
+}
+
+func needSkipLink(flags HTMLFlags, dest []byte) bool {
+	if flags&SkipLinks != 0 {
+		return true
+	}
+	return flags&Safelink != 0 && !isSafeLink(dest) && !isMailto(dest)
+}
+
+func isSmartypantable(node *Node) bool {
+	pt := node.Parent.Type
+	return pt != Link && pt != CodeBlock && pt != Code
+}
+
+func appendLanguageAttr(attrs []string, info []byte) []string {
+	if len(info) == 0 {
+		return attrs
+	}
+	endOfLang := bytes.IndexAny(info, "\t ")
+	if endOfLang < 0 {
+		endOfLang = len(info)
+	}
+	return append(attrs, fmt.Sprintf("class=\"language-%s\"", info[:endOfLang]))
+}
+
+func (r *HTMLRenderer) tag(w io.Writer, name []byte, attrs []string) {
+	w.Write(name)
+	if len(attrs) > 0 {
+		w.Write(spaceBytes)
+		w.Write([]byte(strings.Join(attrs, " ")))
+	}
+	w.Write(gtBytes)
+	r.lastOutputLen = 1
+}
+
+func footnoteRef(prefix string, node *Node) []byte {
+	urlFrag := prefix + string(slugify(node.Destination))
+	anchor := fmt.Sprintf(`<a href="#fn:%s">%d</a>`, urlFrag, node.NoteID)
+	return []byte(fmt.Sprintf(`<sup class="footnote-ref" id="fnref:%s">%s</sup>`, urlFrag, anchor))
+}
+
+func footnoteItem(prefix string, slug []byte) []byte {
+	return []byte(fmt.Sprintf(`<li id="fn:%s%s">`, prefix, slug))
+}
+
+func footnoteReturnLink(prefix, returnLink string, slug []byte) []byte {
+	const format = ` <a class="footnote-return" href="#fnref:%s%s">%s</a>`
+	return []byte(fmt.Sprintf(format, prefix, slug, returnLink))
+}
+
+func itemOpenCR(node *Node) bool {
+	if node.Prev == nil {
+		return false
+	}
+	ld := node.Parent.ListData
+	return !ld.Tight && ld.ListFlags&ListTypeDefinition == 0
+}
+
+func skipParagraphTags(node *Node) bool {
+	grandparent := node.Parent.Parent
+	if grandparent == nil || grandparent.Type != List {
+		return false
+	}
+	tightOrTerm := grandparent.Tight || node.Parent.ListFlags&ListTypeTerm != 0
+	return grandparent.Type == List && tightOrTerm
+}
+
+func cellAlignment(align CellAlignFlags) string {
+	switch align {
+	case TableAlignmentLeft:
+		return "left"
+	case TableAlignmentRight:
+		return "right"
+	case TableAlignmentCenter:
+		return "center"
+	default:
+		return ""
+	}
+}
+
+func (r *HTMLRenderer) out(w io.Writer, text []byte) {
+	if r.disableTags > 0 {
+		w.Write(htmlTagRe.ReplaceAll(text, []byte{}))
+	} else {
+		w.Write(text)
+	}
+	r.lastOutputLen = len(text)
+}
+
+func (r *HTMLRenderer) cr(w io.Writer) {
+	if r.lastOutputLen > 0 {
+		r.out(w, nlBytes)
+	}
+}
+
+var (
+	nlBytes    = []byte{'\n'}
+	gtBytes    = []byte{'>'}
+	spaceBytes = []byte{' '}
+)
+
+var (
+	brTag              = []byte("<br>")
+	brXHTMLTag         = []byte("<br />")
+	emTag              = []byte("<em>")
+	emCloseTag         = []byte("</em>")
+	strongTag          = []byte("<strong>")
+	strongCloseTag     = []byte("</strong>")
+	delTag             = []byte("<del>")
+	delCloseTag        = []byte("</del>")
+	ttTag              = []byte("<tt>")
+	ttCloseTag         = []byte("</tt>")
+	aTag               = []byte("<a")
+	aCloseTag          = []byte("</a>")
+	preTag             = []byte("<pre>")
+	preCloseTag        = []byte("</pre>")
+	codeTag            = []byte("<code>")
+	codeCloseTag       = []byte("</code>")
+	pTag               = []byte("<p>")
+	pCloseTag          = []byte("</p>")
+	blockquoteTag      = []byte("<blockquote>")
+	blockquoteCloseTag = []byte("</blockquote>")
+	hrTag              = []byte("<hr>")
+	hrXHTMLTag         = []byte("<hr />")
+	ulTag              = []byte("<ul>")
+	ulCloseTag         = []byte("</ul>")
+	olTag              = []byte("<ol>")
+	olCloseTag         = []byte("</ol>")
+	dlTag              = []byte("<dl>")
+	dlCloseTag         = []byte("</dl>")
+	liTag              = []byte("<li>")
+	liCloseTag         = []byte("</li>")
+	ddTag              = []byte("<dd>")
+	ddCloseTag         = []byte("</dd>")
+	dtTag              = []byte("<dt>")
+	dtCloseTag         = []byte("</dt>")
+	tableTag           = []byte("<table>")
+	tableCloseTag      = []byte("</table>")
+	tdTag              = []byte("<td")
+	tdCloseTag         = []byte("</td>")
+	thTag              = []byte("<th")
+	thCloseTag         = []byte("</th>")
+	theadTag           = []byte("<thead>")
+	theadCloseTag      = []byte("</thead>")
+	tbodyTag           = []byte("<tbody>")
+	tbodyCloseTag      = []byte("</tbody>")
+	trTag              = []byte("<tr>")
+	trCloseTag         = []byte("</tr>")
+	h1Tag              = []byte("<h1")
+	h1CloseTag         = []byte("</h1>")
+	h2Tag              = []byte("<h2")
+	h2CloseTag         = []byte("</h2>")
+	h3Tag              = []byte("<h3")
+	h3CloseTag         = []byte("</h3>")
+	h4Tag              = []byte("<h4")
+	h4CloseTag         = []byte("</h4>")
+	h5Tag              = []byte("<h5")
+	h5CloseTag         = []byte("</h5>")
+	h6Tag              = []byte("<h6")
+	h6CloseTag         = []byte("</h6>")
+
+	footnotesDivBytes      = []byte("\n<div class=\"footnotes\">\n\n")
+	footnotesCloseDivBytes = []byte("\n</div>\n")
+)
+
+func headingTagsFromLevel(level int) ([]byte, []byte) {
+	if level <= 1 {
+		return h1Tag, h1CloseTag
+	}
+	switch level {
+	case 2:
+		return h2Tag, h2CloseTag
+	case 3:
+		return h3Tag, h3CloseTag
+	case 4:
+		return h4Tag, h4CloseTag
+	case 5:
+		return h5Tag, h5CloseTag
+	}
+	return h6Tag, h6CloseTag
+}
+
+func (r *HTMLRenderer) outHRTag(w io.Writer) {
+	if r.Flags&UseXHTML == 0 {
+		r.out(w, hrTag)
+	} else {
+		r.out(w, hrXHTMLTag)
+	}
+}
+
+// RenderNode is a default renderer of a single node of a syntax tree. For
+// block nodes it will be called twice: first time with entering=true, second
+// time with entering=false, so that it could know when it's working on an open
+// tag and when on close. It writes the result to w.
+//
+// The return value is a way to tell the calling walker to adjust its walk
+// pattern: e.g. it can terminate the traversal by returning Terminate. Or it
+// can ask the walker to skip a subtree of this node by returning SkipChildren.
+// The typical behavior is to return GoToNext, which asks for the usual
+// traversal to the next node.
+func (r *HTMLRenderer) RenderNode(w io.Writer, node *Node, entering bool) WalkStatus {
+	attrs := []string{}
+	switch node.Type {
+	case Text:
+		if r.Flags&Smartypants != 0 {
+			var tmp bytes.Buffer
+			escapeHTML(&tmp, node.Literal)
+			r.sr.Process(w, tmp.Bytes())
+		} else {
+			if node.Parent.Type == Link {
+				escLink(w, node.Literal)
+			} else {
+				escapeHTML(w, node.Literal)
+			}
+		}
+	case Softbreak:
+		r.cr(w)
+		// TODO: make it configurable via out(renderer.softbreak)
+	case Hardbreak:
+		if r.Flags&UseXHTML == 0 {
+			r.out(w, brTag)
+		} else {
+			r.out(w, brXHTMLTag)
+		}
+		r.cr(w)
+	case Emph:
+		if entering {
+			r.out(w, emTag)
+		} else {
+			r.out(w, emCloseTag)
+		}
+	case Strong:
+		if entering {
+			r.out(w, strongTag)
+		} else {
+			r.out(w, strongCloseTag)
+		}
+	case Del:
+		if entering {
+			r.out(w, delTag)
+		} else {
+			r.out(w, delCloseTag)
+		}
+	case HTMLSpan:
+		if r.Flags&SkipHTML != 0 {
+			break
+		}
+		r.out(w, node.Literal)
+	case Link:
+		// mark it but don't link it if it is not a safe link: no smartypants
+		dest := node.LinkData.Destination
+		if needSkipLink(r.Flags, dest) {
+			if entering {
+				r.out(w, ttTag)
+			} else {
+				r.out(w, ttCloseTag)
+			}
+		} else {
+			if entering {
+				dest = r.addAbsPrefix(dest)
+				var hrefBuf bytes.Buffer
+				hrefBuf.WriteString("href=\"")
+				escLink(&hrefBuf, dest)
+				hrefBuf.WriteByte('"')
+				attrs = append(attrs, hrefBuf.String())
+				if node.NoteID != 0 {
+					r.out(w, footnoteRef(r.FootnoteAnchorPrefix, node))
+					break
+				}
+				attrs = appendLinkAttrs(attrs, r.Flags, dest)
+				if len(node.LinkData.Title) > 0 {
+					var titleBuff bytes.Buffer
+					titleBuff.WriteString("title=\"")
+					escapeHTML(&titleBuff, node.LinkData.Title)
+					titleBuff.WriteByte('"')
+					attrs = append(attrs, titleBuff.String())
+				}
+				r.tag(w, aTag, attrs)
+			} else {
+				if node.NoteID != 0 {
+					break
+				}
+				r.out(w, aCloseTag)
+			}
+		}
+	case Image:
+		if r.Flags&SkipImages != 0 {
+			return SkipChildren
+		}
+		if entering {
+			dest := node.LinkData.Destination
+			dest = r.addAbsPrefix(dest)
+			if r.disableTags == 0 {
+				//if options.safe && potentiallyUnsafe(dest) {
+				//out(w, `<img src="" alt="`)
+				//} else {
+				r.out(w, []byte(`<img src="`))
+				escLink(w, dest)
+				r.out(w, []byte(`" alt="`))
+				//}
+			}
+			r.disableTags++
+		} else {
+			r.disableTags--
+			if r.disableTags == 0 {
+				if node.LinkData.Title != nil {
+					r.out(w, []byte(`" title="`))
+					escapeHTML(w, node.LinkData.Title)
+				}
+				r.out(w, []byte(`" />`))
+			}
+		}
+	case Code:
+		r.out(w, codeTag)
+		escapeHTML(w, node.Literal)
+		r.out(w, codeCloseTag)
+	case Document:
+		break
+	case Paragraph:
+		if skipParagraphTags(node) {
+			break
+		}
+		if entering {
+			// TODO: untangle this clusterfuck about when the newlines need
+			// to be added and when not.
+			if node.Prev != nil {
+				switch node.Prev.Type {
+				case HTMLBlock, List, Paragraph, Heading, CodeBlock, BlockQuote, HorizontalRule:
+					r.cr(w)
+				}
+			}
+			if node.Parent.Type == BlockQuote && node.Prev == nil {
+				r.cr(w)
+			}
+			r.out(w, pTag)
+		} else {
+			r.out(w, pCloseTag)
+			if !(node.Parent.Type == Item && node.Next == nil) {
+				r.cr(w)
+			}
+		}
+	case BlockQuote:
+		if entering {
+			r.cr(w)
+			r.out(w, blockquoteTag)
+		} else {
+			r.out(w, blockquoteCloseTag)
+			r.cr(w)
+		}
+	case HTMLBlock:
+		if r.Flags&SkipHTML != 0 {
+			break
+		}
+		r.cr(w)
+		r.out(w, node.Literal)
+		r.cr(w)
+	case Heading:
+		headingLevel := r.HTMLRendererParameters.HeadingLevelOffset + node.Level
+		openTag, closeTag := headingTagsFromLevel(headingLevel)
+		if entering {
+			if node.IsTitleblock {
+				attrs = append(attrs, `class="title"`)
+			}
+			if node.HeadingID != "" {
+				id := r.ensureUniqueHeadingID(node.HeadingID)
+				if r.HeadingIDPrefix != "" {
+					id = r.HeadingIDPrefix + id
+				}
+				if r.HeadingIDSuffix != "" {
+					id = id + r.HeadingIDSuffix
+				}
+				attrs = append(attrs, fmt.Sprintf(`id="%s"`, id))
+			}
+			r.cr(w)
+			r.tag(w, openTag, attrs)
+		} else {
+			r.out(w, closeTag)
+			if !(node.Parent.Type == Item && node.Next == nil) {
+				r.cr(w)
+			}
+		}
+	case HorizontalRule:
+		r.cr(w)
+		r.outHRTag(w)
+		r.cr(w)
+	case List:
+		openTag := ulTag
+		closeTag := ulCloseTag
+		if node.ListFlags&ListTypeOrdered != 0 {
+			openTag = olTag
+			closeTag = olCloseTag
+		}
+		if node.ListFlags&ListTypeDefinition != 0 {
+			openTag = dlTag
+			closeTag = dlCloseTag
+		}
+		if entering {
+			if node.IsFootnotesList {
+				r.out(w, footnotesDivBytes)
+				r.outHRTag(w)
+				r.cr(w)
+			}
+			r.cr(w)
+			if node.Parent.Type == Item && node.Parent.Parent.Tight {
+				r.cr(w)
+			}
+			r.tag(w, openTag[:len(openTag)-1], attrs)
+			r.cr(w)
+		} else {
+			r.out(w, closeTag)
+			//cr(w)
+			//if node.parent.Type != Item {
+			//	cr(w)
+			//}
+			if node.Parent.Type == Item && node.Next != nil {
+				r.cr(w)
+			}
+			if node.Parent.Type == Document || node.Parent.Type == BlockQuote {
+				r.cr(w)
+			}
+			if node.IsFootnotesList {
+				r.out(w, footnotesCloseDivBytes)
+			}
+		}
+	case Item:
+		openTag := liTag
+		closeTag := liCloseTag
+		if node.ListFlags&ListTypeDefinition != 0 {
+			openTag = ddTag
+			closeTag = ddCloseTag
+		}
+		if node.ListFlags&ListTypeTerm != 0 {
+			openTag = dtTag
+			closeTag = dtCloseTag
+		}
+		if entering {
+			if itemOpenCR(node) {
+				r.cr(w)
+			}
+			if node.ListData.RefLink != nil {
+				slug := slugify(node.ListData.RefLink)
+				r.out(w, footnoteItem(r.FootnoteAnchorPrefix, slug))
+				break
+			}
+			r.out(w, openTag)
+		} else {
+			if node.ListData.RefLink != nil {
+				slug := slugify(node.ListData.RefLink)
+				if r.Flags&FootnoteReturnLinks != 0 {
+					r.out(w, footnoteReturnLink(r.FootnoteAnchorPrefix, r.FootnoteReturnLinkContents, slug))
+				}
+			}
+			r.out(w, closeTag)
+			r.cr(w)
+		}
+	case CodeBlock:
+		attrs = appendLanguageAttr(attrs, node.Info)
+		r.cr(w)
+		r.out(w, preTag)
+		r.tag(w, codeTag[:len(codeTag)-1], attrs)
+		escapeHTML(w, node.Literal)
+		r.out(w, codeCloseTag)
+		r.out(w, preCloseTag)
+		if node.Parent.Type != Item {
+			r.cr(w)
+		}
+	case Table:
+		if entering {
+			r.cr(w)
+			r.out(w, tableTag)
+		} else {
+			r.out(w, tableCloseTag)
+			r.cr(w)
+		}
+	case TableCell:
+		openTag := tdTag
+		closeTag := tdCloseTag
+		if node.IsHeader {
+			openTag = thTag
+			closeTag = thCloseTag
+		}
+		if entering {
+			align := cellAlignment(node.Align)
+			if align != "" {
+				attrs = append(attrs, fmt.Sprintf(`align="%s"`, align))
+			}
+			if node.Prev == nil {
+				r.cr(w)
+			}
+			r.tag(w, openTag, attrs)
+		} else {
+			r.out(w, closeTag)
+			r.cr(w)
+		}
+	case TableHead:
+		if entering {
+			r.cr(w)
+			r.out(w, theadTag)
+		} else {
+			r.out(w, theadCloseTag)
+			r.cr(w)
+		}
+	case TableBody:
+		if entering {
+			r.cr(w)
+			r.out(w, tbodyTag)
+			// XXX: this is to adhere to a rather silly test. Should fix test.
+			if node.FirstChild == nil {
+				r.cr(w)
+			}
+		} else {
+			r.out(w, tbodyCloseTag)
+			r.cr(w)
+		}
+	case TableRow:
+		if entering {
+			r.cr(w)
+			r.out(w, trTag)
+		} else {
+			r.out(w, trCloseTag)
+			r.cr(w)
+		}
+	default:
+		panic("Unknown node type " + node.Type.String())
+	}
+	return GoToNext
+}
+
+// RenderHeader writes HTML document preamble and TOC if requested.
+func (r *HTMLRenderer) RenderHeader(w io.Writer, ast *Node) {
+	r.writeDocumentHeader(w)
+	if r.Flags&TOC != 0 {
+		r.writeTOC(w, ast)
+	}
+}
+
+// RenderFooter writes HTML document footer.
+func (r *HTMLRenderer) RenderFooter(w io.Writer, ast *Node) {
+	if r.Flags&CompletePage == 0 {
+		return
+	}
+	io.WriteString(w, "\n</body>\n</html>\n")
+}
+
+func (r *HTMLRenderer) writeDocumentHeader(w io.Writer) {
+	if r.Flags&CompletePage == 0 {
+		return
+	}
+	ending := ""
+	if r.Flags&UseXHTML != 0 {
+		io.WriteString(w, "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\" ")
+		io.WriteString(w, "\"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">\n")
+		io.WriteString(w, "<html xmlns=\"http://www.w3.org/1999/xhtml\">\n")
+		ending = " /"
+	} else {
+		io.WriteString(w, "<!DOCTYPE html>\n")
+		io.WriteString(w, "<html>\n")
+	}
+	io.WriteString(w, "<head>\n")
+	io.WriteString(w, "  <title>")
+	if r.Flags&Smartypants != 0 {
+		r.sr.Process(w, []byte(r.Title))
+	} else {
+		escapeHTML(w, []byte(r.Title))
+	}
+	io.WriteString(w, "</title>\n")
+	io.WriteString(w, "  <meta name=\"GENERATOR\" content=\"Blackfriday Markdown Processor v")
+	io.WriteString(w, Version)
+	io.WriteString(w, "\"")
+	io.WriteString(w, ending)
+	io.WriteString(w, ">\n")
+	io.WriteString(w, "  <meta charset=\"utf-8\"")
+	io.WriteString(w, ending)
+	io.WriteString(w, ">\n")
+	if r.CSS != "" {
+		io.WriteString(w, "  <link rel=\"stylesheet\" type=\"text/css\" href=\"")
+		escapeHTML(w, []byte(r.CSS))
+		io.WriteString(w, "\"")
+		io.WriteString(w, ending)
+		io.WriteString(w, ">\n")
+	}
+	if r.Icon != "" {
+		io.WriteString(w, "  <link rel=\"icon\" type=\"image/x-icon\" href=\"")
+		escapeHTML(w, []byte(r.Icon))
+		io.WriteString(w, "\"")
+		io.WriteString(w, ending)
+		io.WriteString(w, ">\n")
+	}
+	io.WriteString(w, "</head>\n")
+	io.WriteString(w, "<body>\n\n")
+}
+
+func (r *HTMLRenderer) writeTOC(w io.Writer, ast *Node) {
+	buf := bytes.Buffer{}
+
+	inHeading := false
+	tocLevel := 0
+	headingCount := 0
+
+	ast.Walk(func(node *Node, entering bool) WalkStatus {
+		if node.Type == Heading && !node.HeadingData.IsTitleblock {
+			inHeading = entering
+			if entering {
+				node.HeadingID = fmt.Sprintf("toc_%d", headingCount)
+				if node.Level == tocLevel {
+					buf.WriteString("</li>\n\n<li>")
+				} else if node.Level < tocLevel {
+					for node.Level < tocLevel {
+						tocLevel--
+						buf.WriteString("</li>\n</ul>")
+					}
+					buf.WriteString("</li>\n\n<li>")
+				} else {
+					for node.Level > tocLevel {
+						tocLevel++
+						buf.WriteString("\n<ul>\n<li>")
+					}
+				}
+
+				fmt.Fprintf(&buf, `<a href="#toc_%d">`, headingCount)
+				headingCount++
+			} else {
+				buf.WriteString("</a>")
+			}
+			return GoToNext
+		}
+
+		if inHeading {
+			return r.RenderNode(&buf, node, entering)
+		}
+
+		return GoToNext
+	})
+
+	for ; tocLevel > 0; tocLevel-- {
+		buf.WriteString("</li>\n</ul>")
+	}
+
+	if buf.Len() > 0 {
+		io.WriteString(w, "<nav>\n")
+		w.Write(buf.Bytes())
+		io.WriteString(w, "\n\n</nav>\n")
+	}
+	r.lastOutputLen = buf.Len()
+}
diff --git a/vendor/github.com/russross/blackfriday/inline.go b/vendor/github.com/russross/blackfriday/v2/inline.go
similarity index 63%
rename from vendor/github.com/russross/blackfriday/inline.go
rename to vendor/github.com/russross/blackfriday/v2/inline.go
index cb00ed68e0..4ed2907921 100644
--- a/vendor/github.com/russross/blackfriday/inline.go
+++ b/vendor/github.com/russross/blackfriday/v2/inline.go
@@ -22,6 +22,23 @@ import (
 var (
 	urlRe    = `((https?|ftp):\/\/|\/)[-A-Za-z0-9+&@#\/%?=~_|!:,.;\(\)]+`
 	anchorRe = regexp.MustCompile(`^(<a\shref="` + urlRe + `"(\stitle="[^"<>]+")?\s?>` + urlRe + `<\/a>)`)
+
+	// https://www.w3.org/TR/html5/syntax.html#character-references
+	// highest unicode code point in 17 planes (2^20): 1,114,112d =
+	// 7 dec digits or 6 hex digits
+	// named entity references can be 2-31 characters with stuff like &lt;
+	// at one end and &CounterClockwiseContourIntegral; at the other. There
+	// are also sometimes numbers at the end, although this isn't inherent
+	// in the specification; there are never numbers anywhere else in
+	// current character references, though; see &frac34; and &blk12;, etc.
+	// https://www.w3.org/TR/html5/syntax.html#named-character-references
+	//
+	// entity := "&" (named group | number ref) ";"
+	// named group := [a-zA-Z]{2,31}[0-9]{0,2}
+	// number ref := "#" (dec ref | hex ref)
+	// dec ref := [0-9]{1,7}
+	// hex ref := ("x" | "X") [0-9a-fA-F]{1,6}
+	htmlEntityRe = regexp.MustCompile(`&([a-zA-Z]{2,31}[0-9]{0,2}|#([0-9]{1,7}|[xX][0-9a-fA-F]{1,6}));`)
 )
 
 // Functions to parse text within a block
@@ -29,87 +46,89 @@ var (
 // data is the complete block being rendered
 // offset is the number of valid chars before the current cursor
 
-func (p *parser) inline(out *bytes.Buffer, data []byte) {
-	// this is called recursively: enforce a maximum depth
-	if p.nesting >= p.maxNesting {
+func (p *Markdown) inline(currBlock *Node, data []byte) {
+	// handlers might call us recursively: enforce a maximum depth
+	if p.nesting >= p.maxNesting || len(data) == 0 {
 		return
 	}
 	p.nesting++
-
-	i, end := 0, 0
-	for i < len(data) {
-		// copy inactive chars into the output
-		for end < len(data) && p.inlineCallback[data[end]] == nil {
+	beg, end := 0, 0
+	for end < len(data) {
+		handler := p.inlineCallback[data[end]]
+		if handler != nil {
+			if consumed, node := handler(p, data, end); consumed == 0 {
+				// No action from the callback.
+				end++
+			} else {
+				// Copy inactive chars into the output.
+				currBlock.AppendChild(text(data[beg:end]))
+				if node != nil {
+					currBlock.AppendChild(node)
+				}
+				// Skip past whatever the callback used.
+				beg = end + consumed
+				end = beg
+			}
+		} else {
 			end++
 		}
-
-		p.r.NormalText(out, data[i:end])
-
-		if end >= len(data) {
-			break
-		}
-		i = end
-
-		// call the trigger
-		handler := p.inlineCallback[data[end]]
-		if consumed := handler(p, out, data, i); consumed == 0 {
-			// no action from the callback; buffer the byte for later
-			end = i + 1
-		} else {
-			// skip past whatever the callback used
-			i += consumed
-			end = i
-		}
 	}
-
+	if beg < len(data) {
+		if data[end-1] == '\n' {
+			end--
+		}
+		currBlock.AppendChild(text(data[beg:end]))
+	}
 	p.nesting--
 }
 
 // single and double emphasis parsing
-func emphasis(p *parser, out *bytes.Buffer, data []byte, offset int) int {
+func emphasis(p *Markdown, data []byte, offset int) (int, *Node) {
 	data = data[offset:]
 	c := data[0]
-	ret := 0
 
 	if len(data) > 2 && data[1] != c {
 		// whitespace cannot follow an opening emphasis;
 		// strikethrough only takes two characters '~~'
 		if c == '~' || isspace(data[1]) {
-			return 0
+			return 0, nil
 		}
-		if ret = helperEmphasis(p, out, data[1:], c); ret == 0 {
-			return 0
+		ret, node := helperEmphasis(p, data[1:], c)
+		if ret == 0 {
+			return 0, nil
 		}
 
-		return ret + 1
+		return ret + 1, node
 	}
 
 	if len(data) > 3 && data[1] == c && data[2] != c {
 		if isspace(data[2]) {
-			return 0
+			return 0, nil
 		}
-		if ret = helperDoubleEmphasis(p, out, data[2:], c); ret == 0 {
-			return 0
+		ret, node := helperDoubleEmphasis(p, data[2:], c)
+		if ret == 0 {
+			return 0, nil
 		}
 
-		return ret + 2
+		return ret + 2, node
 	}
 
 	if len(data) > 4 && data[1] == c && data[2] == c && data[3] != c {
 		if c == '~' || isspace(data[3]) {
-			return 0
+			return 0, nil
 		}
-		if ret = helperTripleEmphasis(p, out, data, 3, c); ret == 0 {
-			return 0
+		ret, node := helperTripleEmphasis(p, data, 3, c)
+		if ret == 0 {
+			return 0, nil
 		}
 
-		return ret + 3
+		return ret + 3, node
 	}
 
-	return 0
+	return 0, nil
 }
 
-func codeSpan(p *parser, out *bytes.Buffer, data []byte, offset int) int {
+func codeSpan(p *Markdown, data []byte, offset int) (int, *Node) {
 	data = data[offset:]
 
 	nb := 0
@@ -131,7 +150,7 @@ func codeSpan(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 
 	// no matching delimiter?
 	if i < nb && end >= len(data) {
-		return 0
+		return 0, nil
 	}
 
 	// trim outside whitespace
@@ -147,39 +166,36 @@ func codeSpan(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 
 	// render the code span
 	if fBegin != fEnd {
-		p.r.CodeSpan(out, data[fBegin:fEnd])
+		code := NewNode(Code)
+		code.Literal = data[fBegin:fEnd]
+		return end, code
 	}
 
-	return end
-
+	return end, nil
 }
 
 // newline preceded by two spaces becomes <br>
-// newline without two spaces works when EXTENSION_HARD_LINE_BREAK is enabled
-func lineBreak(p *parser, out *bytes.Buffer, data []byte, offset int) int {
-	// remove trailing spaces from out
-	outBytes := out.Bytes()
-	end := len(outBytes)
-	eol := end
-	for eol > 0 && outBytes[eol-1] == ' ' {
-		eol--
-	}
-	out.Truncate(eol)
-
-	precededByTwoSpaces := offset >= 2 && data[offset-2] == ' ' && data[offset-1] == ' '
-	precededByBackslash := offset >= 1 && data[offset-1] == '\\' // see http://spec.commonmark.org/0.18/#example-527
-	precededByBackslash = precededByBackslash && p.flags&EXTENSION_BACKSLASH_LINE_BREAK != 0
-
-	// should there be a hard line break here?
-	if p.flags&EXTENSION_HARD_LINE_BREAK == 0 && !precededByTwoSpaces && !precededByBackslash {
-		return 0
+func maybeLineBreak(p *Markdown, data []byte, offset int) (int, *Node) {
+	origOffset := offset
+	for offset < len(data) && data[offset] == ' ' {
+		offset++
 	}
 
-	if precededByBackslash && eol > 0 {
-		out.Truncate(eol - 1)
+	if offset < len(data) && data[offset] == '\n' {
+		if offset-origOffset >= 2 {
+			return offset - origOffset + 1, NewNode(Hardbreak)
+		}
+		return offset - origOffset, nil
 	}
-	p.r.LineBreak(out)
-	return 1
+	return 0, nil
+}
+
+// newline without two spaces works when HardLineBreak is enabled
+func lineBreak(p *Markdown, data []byte, offset int) (int, *Node) {
+	if p.extensions&HardLineBreak != 0 {
+		return 1, NewNode(Hardbreak)
+	}
+	return 0, nil
 }
 
 type linkType int
@@ -198,27 +214,43 @@ func isReferenceStyleLink(data []byte, pos int, t linkType) bool {
 	return pos < len(data)-1 && data[pos] == '[' && data[pos+1] != '^'
 }
 
+func maybeImage(p *Markdown, data []byte, offset int) (int, *Node) {
+	if offset < len(data)-1 && data[offset+1] == '[' {
+		return link(p, data, offset)
+	}
+	return 0, nil
+}
+
+func maybeInlineFootnote(p *Markdown, data []byte, offset int) (int, *Node) {
+	if offset < len(data)-1 && data[offset+1] == '[' {
+		return link(p, data, offset)
+	}
+	return 0, nil
+}
+
 // '[': parse a link or an image or a footnote
-func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
+func link(p *Markdown, data []byte, offset int) (int, *Node) {
 	// no links allowed inside regular links, footnote, and deferred footnotes
 	if p.insideLink && (offset > 0 && data[offset-1] == '[' || len(data)-1 > offset && data[offset+1] == '^') {
-		return 0
+		return 0, nil
 	}
 
 	var t linkType
 	switch {
 	// special case: ![^text] == deferred footnote (that follows something with
 	// an exclamation point)
-	case p.flags&EXTENSION_FOOTNOTES != 0 && len(data)-1 > offset && data[offset+1] == '^':
+	case p.extensions&Footnotes != 0 && len(data)-1 > offset && data[offset+1] == '^':
 		t = linkDeferredFootnote
 	// ![alt] == image
-	case offset > 0 && data[offset-1] == '!':
+	case offset >= 0 && data[offset] == '!':
 		t = linkImg
+		offset++
 	// ^[text] == inline footnote
 	// [^refId] == deferred footnote
-	case p.flags&EXTENSION_FOOTNOTES != 0:
-		if offset > 0 && data[offset-1] == '^' {
+	case p.extensions&Footnotes != 0:
+		if offset >= 0 && data[offset] == '^' {
 			t = linkInlineFootnote
+			offset++
 		} else if len(data)-1 > offset && data[offset+1] == '^' {
 			t = linkDeferredFootnote
 		}
@@ -231,7 +263,7 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 
 	var (
 		i                       = 1
-		noteId                  int
+		noteID                  int
 		title, link, altContent []byte
 		textHasNl               = false
 	)
@@ -240,8 +272,6 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 		i++
 	}
 
-	brace := 0
-
 	// look for the matching closing bracket
 	for level := 1; level > 0 && i < len(data); i++ {
 		switch {
@@ -263,11 +293,12 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 	}
 
 	if i >= len(data) {
-		return 0
+		return 0, nil
 	}
 
 	txtE := i
 	i++
+	var footnoteNode *Node
 
 	// skip any amount of whitespace or newline
 	// (this is much more lax than original markdown syntax)
@@ -275,8 +306,8 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 		i++
 	}
 
-	switch {
 	// inline style link
+	switch {
 	case i < len(data) && data[i] == '(':
 		// skip initial whitespace
 		i++
@@ -287,27 +318,14 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 
 		linkB := i
 
-		// look for link end: ' " ), check for new opening braces and take this
-		// into account, this may lead for overshooting and probably will require
-		// some fine-tuning.
+		// look for link end: ' " )
 	findlinkend:
 		for i < len(data) {
 			switch {
 			case data[i] == '\\':
 				i += 2
 
-			case data[i] == '(':
-				brace++
-				i++
-
-			case data[i] == ')':
-				if brace <= 0 {
-					break findlinkend
-				}
-				brace--
-				i++
-
-			case data[i] == '\'' || data[i] == '"':
+			case data[i] == ')' || data[i] == '\'' || data[i] == '"':
 				break findlinkend
 
 			default:
@@ -316,7 +334,7 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 		}
 
 		if i >= len(data) {
-			return 0
+			return 0, nil
 		}
 		linkE := i
 
@@ -341,7 +359,7 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 			}
 
 			if i >= len(data) {
-				return 0
+				return 0, nil
 			}
 
 			// skip whitespace after title
@@ -393,7 +411,7 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 			i++
 		}
 		if i >= len(data) {
-			return 0
+			return 0, nil
 		}
 		linkE := i
 
@@ -423,7 +441,7 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 		// find the reference with matching id
 		lr, ok := p.getRef(string(id))
 		if !ok {
-			return 0
+			return 0, nil
 		}
 
 		// keep link and title from reference
@@ -460,9 +478,10 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 			}
 		}
 
+		footnoteNode = NewNode(Item)
 		if t == linkInlineFootnote {
 			// create a new reference
-			noteId = len(p.notes) + 1
+			noteID = len(p.notes) + 1
 
 			var fragment []byte
 			if len(id) > 0 {
@@ -473,14 +492,15 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 				}
 				copy(fragment, slugify(id))
 			} else {
-				fragment = append([]byte("footnote-"), []byte(strconv.Itoa(noteId))...)
+				fragment = append([]byte("footnote-"), []byte(strconv.Itoa(noteID))...)
 			}
 
 			ref := &reference{
-				noteId:   noteId,
+				noteID:   noteID,
 				hasBlock: false,
 				link:     fragment,
 				title:    id,
+				footnote: footnoteNode,
 			}
 
 			p.notes = append(p.notes, ref)
@@ -491,11 +511,12 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 			// find the reference with matching id
 			lr, ok := p.getRef(string(id))
 			if !ok {
-				return 0
+				return 0, nil
 			}
 
 			if t == linkDeferredFootnote {
-				lr.noteId = len(p.notes) + 1
+				lr.noteID = len(p.notes) + 1
+				lr.footnote = footnoteNode
 				p.notes = append(p.notes, lr)
 			}
 
@@ -503,27 +524,13 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 			link = lr.link
 			// if inline footnote, title == footnote contents
 			title = lr.title
-			noteId = lr.noteId
+			noteID = lr.noteID
 		}
 
 		// rewind the whitespace
 		i = txtE + 1
 	}
 
-	// build content: img alt is escaped, link content is parsed
-	var content bytes.Buffer
-	if txtE > 1 {
-		if t == linkImg {
-			content.Write(data[1:txtE])
-		} else {
-			// links cannot contain other links, so turn off link parsing temporarily
-			insideLink := p.insideLink
-			p.insideLink = true
-			p.inline(&content, data[1:txtE])
-			p.insideLink = insideLink
-		}
-	}
-
 	var uLink []byte
 	if t == linkNormal || t == linkImg {
 		if len(link) > 0 {
@@ -533,49 +540,54 @@ func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 		}
 
 		// links need something to click on and somewhere to go
-		if len(uLink) == 0 || (t == linkNormal && content.Len() == 0) {
-			return 0
+		if len(uLink) == 0 || (t == linkNormal && txtE <= 1) {
+			return 0, nil
 		}
 	}
 
 	// call the relevant rendering function
+	var linkNode *Node
 	switch t {
 	case linkNormal:
+		linkNode = NewNode(Link)
+		linkNode.Destination = normalizeURI(uLink)
+		linkNode.Title = title
 		if len(altContent) > 0 {
-			p.r.Link(out, uLink, title, altContent)
+			linkNode.AppendChild(text(altContent))
 		} else {
-			p.r.Link(out, uLink, title, content.Bytes())
+			// links cannot contain other links, so turn off link parsing
+			// temporarily and recurse
+			insideLink := p.insideLink
+			p.insideLink = true
+			p.inline(linkNode, data[1:txtE])
+			p.insideLink = insideLink
 		}
 
 	case linkImg:
-		outSize := out.Len()
-		outBytes := out.Bytes()
-		if outSize > 0 && outBytes[outSize-1] == '!' {
-			out.Truncate(outSize - 1)
+		linkNode = NewNode(Image)
+		linkNode.Destination = uLink
+		linkNode.Title = title
+		linkNode.AppendChild(text(data[1:txtE]))
+		i++
+
+	case linkInlineFootnote, linkDeferredFootnote:
+		linkNode = NewNode(Link)
+		linkNode.Destination = link
+		linkNode.Title = title
+		linkNode.NoteID = noteID
+		linkNode.Footnote = footnoteNode
+		if t == linkInlineFootnote {
+			i++
 		}
 
-		p.r.Image(out, uLink, title, content.Bytes())
-
-	case linkInlineFootnote:
-		outSize := out.Len()
-		outBytes := out.Bytes()
-		if outSize > 0 && outBytes[outSize-1] == '^' {
-			out.Truncate(outSize - 1)
-		}
-
-		p.r.FootnoteRef(out, link, noteId)
-
-	case linkDeferredFootnote:
-		p.r.FootnoteRef(out, link, noteId)
-
 	default:
-		return 0
+		return 0, nil
 	}
 
-	return i
+	return i, linkNode
 }
 
-func (p *parser) inlineHTMLComment(out *bytes.Buffer, data []byte) int {
+func (p *Markdown) inlineHTMLComment(data []byte) int {
 	if len(data) < 5 {
 		return 0
 	}
@@ -594,44 +606,75 @@ func (p *parser) inlineHTMLComment(out *bytes.Buffer, data []byte) int {
 	return i + 1
 }
 
+func stripMailto(link []byte) []byte {
+	if bytes.HasPrefix(link, []byte("mailto://")) {
+		return link[9:]
+	} else if bytes.HasPrefix(link, []byte("mailto:")) {
+		return link[7:]
+	} else {
+		return link
+	}
+}
+
+// autolinkType specifies a kind of autolink that gets detected.
+type autolinkType int
+
+// These are the possible flag values for the autolink renderer.
+const (
+	notAutolink autolinkType = iota
+	normalAutolink
+	emailAutolink
+)
+
 // '<' when tags or autolinks are allowed
-func leftAngle(p *parser, out *bytes.Buffer, data []byte, offset int) int {
+func leftAngle(p *Markdown, data []byte, offset int) (int, *Node) {
 	data = data[offset:]
-	altype := LINK_TYPE_NOT_AUTOLINK
-	end := tagLength(data, &altype)
-	if size := p.inlineHTMLComment(out, data); size > 0 {
+	altype, end := tagLength(data)
+	if size := p.inlineHTMLComment(data); size > 0 {
 		end = size
 	}
 	if end > 2 {
-		if altype != LINK_TYPE_NOT_AUTOLINK {
+		if altype != notAutolink {
 			var uLink bytes.Buffer
 			unescapeText(&uLink, data[1:end+1-2])
 			if uLink.Len() > 0 {
-				p.r.AutoLink(out, uLink.Bytes(), altype)
+				link := uLink.Bytes()
+				node := NewNode(Link)
+				node.Destination = link
+				if altype == emailAutolink {
+					node.Destination = append([]byte("mailto:"), link...)
+				}
+				node.AppendChild(text(stripMailto(link)))
+				return end, node
 			}
 		} else {
-			p.r.RawHtmlTag(out, data[:end])
+			htmlTag := NewNode(HTMLSpan)
+			htmlTag.Literal = data[:end]
+			return end, htmlTag
 		}
 	}
 
-	return end
+	return end, nil
 }
 
 // '\\' backslash escape
 var escapeChars = []byte("\\`*_{}[]()#+-.!:|&<>~")
 
-func escape(p *parser, out *bytes.Buffer, data []byte, offset int) int {
+func escape(p *Markdown, data []byte, offset int) (int, *Node) {
 	data = data[offset:]
 
 	if len(data) > 1 {
+		if p.extensions&BackslashLineBreak != 0 && data[1] == '\n' {
+			return 2, NewNode(Hardbreak)
+		}
 		if bytes.IndexByte(escapeChars, data[1]) < 0 {
-			return 0
+			return 0, nil
 		}
 
-		p.r.NormalText(out, data[1:2])
+		return 2, text(data[1:2])
 	}
 
-	return 2
+	return 2, nil
 }
 
 func unescapeText(ob *bytes.Buffer, src []byte) {
@@ -657,7 +700,7 @@ func unescapeText(ob *bytes.Buffer, src []byte) {
 
 // '&' escaped when it doesn't belong to an entity
 // valid entities are assumed to be anything matching &#?[A-Za-z0-9]+;
-func entity(p *parser, out *bytes.Buffer, data []byte, offset int) int {
+func entity(p *Markdown, data []byte, offset int) (int, *Node) {
 	data = data[offset:]
 
 	end := 1
@@ -673,25 +716,70 @@ func entity(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 	if end < len(data) && data[end] == ';' {
 		end++ // real entity
 	} else {
-		return 0 // lone '&'
+		return 0, nil // lone '&'
 	}
 
-	p.r.Entity(out, data[:end])
+	ent := data[:end]
+	// undo &amp; escaping or it will be converted to &amp;amp; by another
+	// escaper in the renderer
+	if bytes.Equal(ent, []byte("&amp;")) {
+		ent = []byte{'&'}
+	}
 
-	return end
+	return end, text(ent)
 }
 
 func linkEndsWithEntity(data []byte, linkEnd int) bool {
-	entityRanges := htmlEntity.FindAllIndex(data[:linkEnd], -1)
+	entityRanges := htmlEntityRe.FindAllIndex(data[:linkEnd], -1)
 	return entityRanges != nil && entityRanges[len(entityRanges)-1][1] == linkEnd
 }
 
-func autoLink(p *parser, out *bytes.Buffer, data []byte, offset int) int {
-	// quick check to rule out most false hits on ':'
-	if p.insideLink || len(data) < offset+3 || data[offset+1] != '/' || data[offset+2] != '/' {
-		return 0
+// hasPrefixCaseInsensitive is a custom implementation of
+//     strings.HasPrefix(strings.ToLower(s), prefix)
+// we rolled our own because ToLower pulls in a huge machinery of lowercasing
+// anything from Unicode and that's very slow. Since this func will only be
+// used on ASCII protocol prefixes, we can take shortcuts.
+func hasPrefixCaseInsensitive(s, prefix []byte) bool {
+	if len(s) < len(prefix) {
+		return false
 	}
+	delta := byte('a' - 'A')
+	for i, b := range prefix {
+		if b != s[i] && b != s[i]+delta {
+			return false
+		}
+	}
+	return true
+}
 
+var protocolPrefixes = [][]byte{
+	[]byte("http://"),
+	[]byte("https://"),
+	[]byte("ftp://"),
+	[]byte("file://"),
+	[]byte("mailto:"),
+}
+
+const shortestPrefix = 6 // len("ftp://"), the shortest of the above
+
+func maybeAutoLink(p *Markdown, data []byte, offset int) (int, *Node) {
+	// quick check to rule out most false hits
+	if p.insideLink || len(data) < offset+shortestPrefix {
+		return 0, nil
+	}
+	for _, prefix := range protocolPrefixes {
+		endOfHead := offset + 8 // 8 is the len() of the longest prefix
+		if endOfHead > len(data) {
+			endOfHead = len(data)
+		}
+		if hasPrefixCaseInsensitive(data[offset:endOfHead], prefix) {
+			return autoLink(p, data, offset)
+		}
+	}
+	return 0, nil
+}
+
+func autoLink(p *Markdown, data []byte, offset int) (int, *Node) {
 	// Now a more expensive check to see if we're not inside an anchor element
 	anchorStart := offset
 	offsetFromAnchor := 0
@@ -702,8 +790,9 @@ func autoLink(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 
 	anchorStr := anchorRe.Find(data[anchorStart:])
 	if anchorStr != nil {
-		out.Write(anchorStr[offsetFromAnchor:])
-		return len(anchorStr) - offsetFromAnchor
+		anchorClose := NewNode(HTMLSpan)
+		anchorClose.Literal = anchorStr[offsetFromAnchor:]
+		return len(anchorStr) - offsetFromAnchor, anchorClose
 	}
 
 	// scan backward for a word boundary
@@ -712,14 +801,14 @@ func autoLink(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 		rewind++
 	}
 	if rewind > 6 { // longest supported protocol is "mailto" which has 6 letters
-		return 0
+		return 0, nil
 	}
 
 	origData := data
 	data = data[offset-rewind:]
 
 	if !isSafeLink(data) {
-		return 0
+		return 0, nil
 	}
 
 	linkEnd := 0
@@ -796,19 +885,17 @@ func autoLink(p *parser, out *bytes.Buffer, data []byte, offset int) int {
 		}
 	}
 
-	// we were triggered on the ':', so we need to rewind the output a bit
-	if out.Len() >= rewind {
-		out.Truncate(len(out.Bytes()) - rewind)
-	}
-
 	var uLink bytes.Buffer
 	unescapeText(&uLink, data[:linkEnd])
 
 	if uLink.Len() > 0 {
-		p.r.AutoLink(out, uLink.Bytes(), LINK_TYPE_NORMAL)
+		node := NewNode(Link)
+		node.Destination = uLink.Bytes()
+		node.AppendChild(text(uLink.Bytes()))
+		return linkEnd, node
 	}
 
-	return linkEnd - rewind
+	return linkEnd, nil
 }
 
 func isEndOfLink(char byte) bool {
@@ -841,17 +928,17 @@ func isSafeLink(link []byte) bool {
 }
 
 // return the length of the given tag, or 0 is it's not valid
-func tagLength(data []byte, autolink *int) int {
+func tagLength(data []byte) (autolink autolinkType, end int) {
 	var i, j int
 
 	// a valid tag can't be shorter than 3 chars
 	if len(data) < 3 {
-		return 0
+		return notAutolink, 0
 	}
 
 	// begins with a '<' optionally followed by '/', followed by letter or number
 	if data[0] != '<' {
-		return 0
+		return notAutolink, 0
 	}
 	if data[1] == '/' {
 		i = 2
@@ -860,11 +947,11 @@ func tagLength(data []byte, autolink *int) int {
 	}
 
 	if !isalnum(data[i]) {
-		return 0
+		return notAutolink, 0
 	}
 
 	// scheme test
-	*autolink = LINK_TYPE_NOT_AUTOLINK
+	autolink = notAutolink
 
 	// try to find the beginning of an URI
 	for i < len(data) && (isalnum(data[i]) || data[i] == '.' || data[i] == '+' || data[i] == '-') {
@@ -873,21 +960,20 @@ func tagLength(data []byte, autolink *int) int {
 
 	if i > 1 && i < len(data) && data[i] == '@' {
 		if j = isMailtoAutoLink(data[i:]); j != 0 {
-			*autolink = LINK_TYPE_EMAIL
-			return i + j
+			return emailAutolink, i + j
 		}
 	}
 
 	if i > 2 && i < len(data) && data[i] == ':' {
-		*autolink = LINK_TYPE_NORMAL
+		autolink = normalAutolink
 		i++
 	}
 
 	// complete autolink test: no whitespace or ' or "
 	switch {
 	case i >= len(data):
-		*autolink = LINK_TYPE_NOT_AUTOLINK
-	case *autolink != 0:
+		autolink = notAutolink
+	case autolink != notAutolink:
 		j = i
 
 		for i < len(data) {
@@ -902,24 +988,20 @@ func tagLength(data []byte, autolink *int) int {
 		}
 
 		if i >= len(data) {
-			return 0
+			return autolink, 0
 		}
 		if i > j && data[i] == '>' {
-			return i + 1
+			return autolink, i + 1
 		}
 
 		// one of the forbidden chars has been found
-		*autolink = LINK_TYPE_NOT_AUTOLINK
+		autolink = notAutolink
 	}
-
-	// look for something looking like a tag end
-	for i < len(data) && data[i] != '>' {
-		i++
+	i += bytes.IndexByte(data[i:], '>')
+	if i < 0 {
+		return autolink, 0
 	}
-	if i >= len(data) {
-		return 0
-	}
-	return i + 1
+	return autolink, i + 1
 }
 
 // look for the address part of a mail autolink and '>'
@@ -938,14 +1020,13 @@ func isMailtoAutoLink(data []byte) int {
 			nb++
 
 		case '-', '.', '_':
-			// Do nothing.
+			break
 
 		case '>':
 			if nb == 1 {
 				return i + 1
-			} else {
-				return 0
 			}
+			return 0
 		default:
 			return 0
 		}
@@ -1008,9 +1089,8 @@ func helperFindEmphChar(data []byte, c byte) int {
 			if data[i] != '[' && data[i] != '(' { // not a link
 				if tmpI > 0 {
 					return tmpI
-				} else {
-					continue
 				}
+				continue
 			}
 			cc := data[i]
 			i++
@@ -1029,7 +1109,7 @@ func helperFindEmphChar(data []byte, c byte) int {
 	return 0
 }
 
-func helperEmphasis(p *parser, out *bytes.Buffer, data []byte, c byte) int {
+func helperEmphasis(p *Markdown, data []byte, c byte) (int, *Node) {
 	i := 0
 
 	// skip one symbol if coming from emph3
@@ -1040,11 +1120,11 @@ func helperEmphasis(p *parser, out *bytes.Buffer, data []byte, c byte) int {
 	for i < len(data) {
 		length := helperFindEmphChar(data[i:], c)
 		if length == 0 {
-			return 0
+			return 0, nil
 		}
 		i += length
 		if i >= len(data) {
-			return 0
+			return 0, nil
 		}
 
 		if i+1 < len(data) && data[i+1] == c {
@@ -1054,52 +1134,46 @@ func helperEmphasis(p *parser, out *bytes.Buffer, data []byte, c byte) int {
 
 		if data[i] == c && !isspace(data[i-1]) {
 
-			if p.flags&EXTENSION_NO_INTRA_EMPHASIS != 0 {
+			if p.extensions&NoIntraEmphasis != 0 {
 				if !(i+1 == len(data) || isspace(data[i+1]) || ispunct(data[i+1])) {
 					continue
 				}
 			}
 
-			var work bytes.Buffer
-			p.inline(&work, data[:i])
-			p.r.Emphasis(out, work.Bytes())
-			return i + 1
+			emph := NewNode(Emph)
+			p.inline(emph, data[:i])
+			return i + 1, emph
 		}
 	}
 
-	return 0
+	return 0, nil
 }
 
-func helperDoubleEmphasis(p *parser, out *bytes.Buffer, data []byte, c byte) int {
+func helperDoubleEmphasis(p *Markdown, data []byte, c byte) (int, *Node) {
 	i := 0
 
 	for i < len(data) {
 		length := helperFindEmphChar(data[i:], c)
 		if length == 0 {
-			return 0
+			return 0, nil
 		}
 		i += length
 
 		if i+1 < len(data) && data[i] == c && data[i+1] == c && i > 0 && !isspace(data[i-1]) {
-			var work bytes.Buffer
-			p.inline(&work, data[:i])
-
-			if work.Len() > 0 {
-				// pick the right renderer
-				if c == '~' {
-					p.r.StrikeThrough(out, work.Bytes())
-				} else {
-					p.r.DoubleEmphasis(out, work.Bytes())
-				}
+			nodeType := Strong
+			if c == '~' {
+				nodeType = Del
 			}
-			return i + 2
+			node := NewNode(nodeType)
+			p.inline(node, data[:i])
+			return i + 2, node
 		}
 		i++
 	}
-	return 0
+	return 0, nil
 }
 
-func helperTripleEmphasis(p *parser, out *bytes.Buffer, data []byte, offset int, c byte) int {
+func helperTripleEmphasis(p *Markdown, data []byte, offset int, c byte) (int, *Node) {
 	i := 0
 	origData := data
 	data = data[offset:]
@@ -1107,7 +1181,7 @@ func helperTripleEmphasis(p *parser, out *bytes.Buffer, data []byte, offset int,
 	for i < len(data) {
 		length := helperFindEmphChar(data[i:], c)
 		if length == 0 {
-			return 0
+			return 0, nil
 		}
 		i += length
 
@@ -1119,30 +1193,36 @@ func helperTripleEmphasis(p *parser, out *bytes.Buffer, data []byte, offset int,
 		switch {
 		case i+2 < len(data) && data[i+1] == c && data[i+2] == c:
 			// triple symbol found
-			var work bytes.Buffer
-
-			p.inline(&work, data[:i])
-			if work.Len() > 0 {
-				p.r.TripleEmphasis(out, work.Bytes())
-			}
-			return i + 3
+			strong := NewNode(Strong)
+			em := NewNode(Emph)
+			strong.AppendChild(em)
+			p.inline(em, data[:i])
+			return i + 3, strong
 		case (i+1 < len(data) && data[i+1] == c):
 			// double symbol found, hand over to emph1
-			length = helperEmphasis(p, out, origData[offset-2:], c)
+			length, node := helperEmphasis(p, origData[offset-2:], c)
 			if length == 0 {
-				return 0
-			} else {
-				return length - 2
+				return 0, nil
 			}
+			return length - 2, node
 		default:
 			// single symbol found, hand over to emph2
-			length = helperDoubleEmphasis(p, out, origData[offset-1:], c)
+			length, node := helperDoubleEmphasis(p, origData[offset-1:], c)
 			if length == 0 {
-				return 0
-			} else {
-				return length - 1
+				return 0, nil
 			}
+			return length - 1, node
 		}
 	}
-	return 0
+	return 0, nil
+}
+
+func text(s []byte) *Node {
+	node := NewNode(Text)
+	node.Literal = s
+	return node
+}
+
+func normalizeURI(s []byte) []byte {
+	return s // TODO: implement
 }
diff --git a/vendor/github.com/russross/blackfriday/v2/markdown.go b/vendor/github.com/russross/blackfriday/v2/markdown.go
new file mode 100644
index 0000000000..58d2e4538c
--- /dev/null
+++ b/vendor/github.com/russross/blackfriday/v2/markdown.go
@@ -0,0 +1,950 @@
+// Blackfriday Markdown Processor
+// Available at http://github.com/russross/blackfriday
+//
+// Copyright © 2011 Russ Ross <russ@russross.com>.
+// Distributed under the Simplified BSD License.
+// See README.md for details.
+
+package blackfriday
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"strings"
+	"unicode/utf8"
+)
+
+//
+// Markdown parsing and processing
+//
+
+// Version string of the package. Appears in the rendered document when
+// CompletePage flag is on.
+const Version = "2.0"
+
+// Extensions is a bitwise or'ed collection of enabled Blackfriday's
+// extensions.
+type Extensions int
+
+// These are the supported markdown parsing extensions.
+// OR these values together to select multiple extensions.
+const (
+	NoExtensions           Extensions = 0
+	NoIntraEmphasis        Extensions = 1 << iota // Ignore emphasis markers inside words
+	Tables                                        // Render tables
+	FencedCode                                    // Render fenced code blocks
+	Autolink                                      // Detect embedded URLs that are not explicitly marked
+	Strikethrough                                 // Strikethrough text using ~~test~~
+	LaxHTMLBlocks                                 // Loosen up HTML block parsing rules
+	SpaceHeadings                                 // Be strict about prefix heading rules
+	HardLineBreak                                 // Translate newlines into line breaks
+	TabSizeEight                                  // Expand tabs to eight spaces instead of four
+	Footnotes                                     // Pandoc-style footnotes
+	NoEmptyLineBeforeBlock                        // No need to insert an empty line to start a (code, quote, ordered list, unordered list) block
+	HeadingIDs                                    // specify heading IDs  with {#id}
+	Titleblock                                    // Titleblock ala pandoc
+	AutoHeadingIDs                                // Create the heading ID from the text
+	BackslashLineBreak                            // Translate trailing backslashes into line breaks
+	DefinitionLists                               // Render definition lists
+
+	CommonHTMLFlags HTMLFlags = UseXHTML | Smartypants |
+		SmartypantsFractions | SmartypantsDashes | SmartypantsLatexDashes
+
+	CommonExtensions Extensions = NoIntraEmphasis | Tables | FencedCode |
+		Autolink | Strikethrough | SpaceHeadings | HeadingIDs |
+		BackslashLineBreak | DefinitionLists
+)
+
+// ListType contains bitwise or'ed flags for list and list item objects.
+type ListType int
+
+// These are the possible flag values for the ListItem renderer.
+// Multiple flag values may be ORed together.
+// These are mostly of interest if you are writing a new output format.
+const (
+	ListTypeOrdered ListType = 1 << iota
+	ListTypeDefinition
+	ListTypeTerm
+
+	ListItemContainsBlock
+	ListItemBeginningOfList // TODO: figure out if this is of any use now
+	ListItemEndOfList
+)
+
+// CellAlignFlags holds a type of alignment in a table cell.
+type CellAlignFlags int
+
+// These are the possible flag values for the table cell renderer.
+// Only a single one of these values will be used; they are not ORed together.
+// These are mostly of interest if you are writing a new output format.
+const (
+	TableAlignmentLeft CellAlignFlags = 1 << iota
+	TableAlignmentRight
+	TableAlignmentCenter = (TableAlignmentLeft | TableAlignmentRight)
+)
+
+// The size of a tab stop.
+const (
+	TabSizeDefault = 4
+	TabSizeDouble  = 8
+)
+
+// blockTags is a set of tags that are recognized as HTML block tags.
+// Any of these can be included in markdown text without special escaping.
+var blockTags = map[string]struct{}{
+	"blockquote": {},
+	"del":        {},
+	"div":        {},
+	"dl":         {},
+	"fieldset":   {},
+	"form":       {},
+	"h1":         {},
+	"h2":         {},
+	"h3":         {},
+	"h4":         {},
+	"h5":         {},
+	"h6":         {},
+	"iframe":     {},
+	"ins":        {},
+	"math":       {},
+	"noscript":   {},
+	"ol":         {},
+	"pre":        {},
+	"p":          {},
+	"script":     {},
+	"style":      {},
+	"table":      {},
+	"ul":         {},
+
+	// HTML5
+	"address":    {},
+	"article":    {},
+	"aside":      {},
+	"canvas":     {},
+	"figcaption": {},
+	"figure":     {},
+	"footer":     {},
+	"header":     {},
+	"hgroup":     {},
+	"main":       {},
+	"nav":        {},
+	"output":     {},
+	"progress":   {},
+	"section":    {},
+	"video":      {},
+}
+
+// Renderer is the rendering interface. This is mostly of interest if you are
+// implementing a new rendering format.
+//
+// Only an HTML implementation is provided in this repository, see the README
+// for external implementations.
+type Renderer interface {
+	// RenderNode is the main rendering method. It will be called once for
+	// every leaf node and twice for every non-leaf node (first with
+	// entering=true, then with entering=false). The method should write its
+	// rendition of the node to the supplied writer w.
+	RenderNode(w io.Writer, node *Node, entering bool) WalkStatus
+
+	// RenderHeader is a method that allows the renderer to produce some
+	// content preceding the main body of the output document. The header is
+	// understood in the broad sense here. For example, the default HTML
+	// renderer will write not only the HTML document preamble, but also the
+	// table of contents if it was requested.
+	//
+	// The method will be passed an entire document tree, in case a particular
+	// implementation needs to inspect it to produce output.
+	//
+	// The output should be written to the supplied writer w. If your
+	// implementation has no header to write, supply an empty implementation.
+	RenderHeader(w io.Writer, ast *Node)
+
+	// RenderFooter is a symmetric counterpart of RenderHeader.
+	RenderFooter(w io.Writer, ast *Node)
+}
+
+// Callback functions for inline parsing. One such function is defined
+// for each character that triggers a response when parsing inline data.
+type inlineParser func(p *Markdown, data []byte, offset int) (int, *Node)
+
+// Markdown is a type that holds extensions and the runtime state used by
+// Parse, and the renderer. You can not use it directly, construct it with New.
+type Markdown struct {
+	renderer          Renderer
+	referenceOverride ReferenceOverrideFunc
+	refs              map[string]*reference
+	inlineCallback    [256]inlineParser
+	extensions        Extensions
+	nesting           int
+	maxNesting        int
+	insideLink        bool
+
+	// Footnotes need to be ordered as well as available to quickly check for
+	// presence. If a ref is also a footnote, it's stored both in refs and here
+	// in notes. Slice is nil if footnotes not enabled.
+	notes []*reference
+
+	doc                  *Node
+	tip                  *Node // = doc
+	oldTip               *Node
+	lastMatchedContainer *Node // = doc
+	allClosed            bool
+}
+
+func (p *Markdown) getRef(refid string) (ref *reference, found bool) {
+	if p.referenceOverride != nil {
+		r, overridden := p.referenceOverride(refid)
+		if overridden {
+			if r == nil {
+				return nil, false
+			}
+			return &reference{
+				link:     []byte(r.Link),
+				title:    []byte(r.Title),
+				noteID:   0,
+				hasBlock: false,
+				text:     []byte(r.Text)}, true
+		}
+	}
+	// refs are case insensitive
+	ref, found = p.refs[strings.ToLower(refid)]
+	return ref, found
+}
+
+func (p *Markdown) finalize(block *Node) {
+	above := block.Parent
+	block.open = false
+	p.tip = above
+}
+
+func (p *Markdown) addChild(node NodeType, offset uint32) *Node {
+	return p.addExistingChild(NewNode(node), offset)
+}
+
+func (p *Markdown) addExistingChild(node *Node, offset uint32) *Node {
+	for !p.tip.canContain(node.Type) {
+		p.finalize(p.tip)
+	}
+	p.tip.AppendChild(node)
+	p.tip = node
+	return node
+}
+
+func (p *Markdown) closeUnmatchedBlocks() {
+	if !p.allClosed {
+		for p.oldTip != p.lastMatchedContainer {
+			parent := p.oldTip.Parent
+			p.finalize(p.oldTip)
+			p.oldTip = parent
+		}
+		p.allClosed = true
+	}
+}
+
+//
+//
+// Public interface
+//
+//
+
+// Reference represents the details of a link.
+// See the documentation in Options for more details on use-case.
+type Reference struct {
+	// Link is usually the URL the reference points to.
+	Link string
+	// Title is the alternate text describing the link in more detail.
+	Title string
+	// Text is the optional text to override the ref with if the syntax used was
+	// [refid][]
+	Text string
+}
+
+// ReferenceOverrideFunc is expected to be called with a reference string and
+// return either a valid Reference type that the reference string maps to or
+// nil. If overridden is false, the default reference logic will be executed.
+// See the documentation in Options for more details on use-case.
+type ReferenceOverrideFunc func(reference string) (ref *Reference, overridden bool)
+
+// New constructs a Markdown processor. You can use the same With* functions as
+// for Run() to customize parser's behavior and the renderer.
+func New(opts ...Option) *Markdown {
+	var p Markdown
+	for _, opt := range opts {
+		opt(&p)
+	}
+	p.refs = make(map[string]*reference)
+	p.maxNesting = 16
+	p.insideLink = false
+	docNode := NewNode(Document)
+	p.doc = docNode
+	p.tip = docNode
+	p.oldTip = docNode
+	p.lastMatchedContainer = docNode
+	p.allClosed = true
+	// register inline parsers
+	p.inlineCallback[' '] = maybeLineBreak
+	p.inlineCallback['*'] = emphasis
+	p.inlineCallback['_'] = emphasis
+	if p.extensions&Strikethrough != 0 {
+		p.inlineCallback['~'] = emphasis
+	}
+	p.inlineCallback['`'] = codeSpan
+	p.inlineCallback['\n'] = lineBreak
+	p.inlineCallback['['] = link
+	p.inlineCallback['<'] = leftAngle
+	p.inlineCallback['\\'] = escape
+	p.inlineCallback['&'] = entity
+	p.inlineCallback['!'] = maybeImage
+	p.inlineCallback['^'] = maybeInlineFootnote
+	if p.extensions&Autolink != 0 {
+		p.inlineCallback['h'] = maybeAutoLink
+		p.inlineCallback['m'] = maybeAutoLink
+		p.inlineCallback['f'] = maybeAutoLink
+		p.inlineCallback['H'] = maybeAutoLink
+		p.inlineCallback['M'] = maybeAutoLink
+		p.inlineCallback['F'] = maybeAutoLink
+	}
+	if p.extensions&Footnotes != 0 {
+		p.notes = make([]*reference, 0)
+	}
+	return &p
+}
+
+// Option customizes the Markdown processor's default behavior.
+type Option func(*Markdown)
+
+// WithRenderer allows you to override the default renderer.
+func WithRenderer(r Renderer) Option {
+	return func(p *Markdown) {
+		p.renderer = r
+	}
+}
+
+// WithExtensions allows you to pick some of the many extensions provided by
+// Blackfriday. You can bitwise OR them.
+func WithExtensions(e Extensions) Option {
+	return func(p *Markdown) {
+		p.extensions = e
+	}
+}
+
+// WithNoExtensions turns off all extensions and custom behavior.
+func WithNoExtensions() Option {
+	return func(p *Markdown) {
+		p.extensions = NoExtensions
+		p.renderer = NewHTMLRenderer(HTMLRendererParameters{
+			Flags: HTMLFlagsNone,
+		})
+	}
+}
+
+// WithRefOverride sets an optional function callback that is called every
+// time a reference is resolved.
+//
+// In Markdown, the link reference syntax can be made to resolve a link to
+// a reference instead of an inline URL, in one of the following ways:
+//
+//  * [link text][refid]
+//  * [refid][]
+//
+// Usually, the refid is defined at the bottom of the Markdown document. If
+// this override function is provided, the refid is passed to the override
+// function first, before consulting the defined refids at the bottom. If
+// the override function indicates an override did not occur, the refids at
+// the bottom will be used to fill in the link details.
+func WithRefOverride(o ReferenceOverrideFunc) Option {
+	return func(p *Markdown) {
+		p.referenceOverride = o
+	}
+}
+
+// Run is the main entry point to Blackfriday. It parses and renders a
+// block of markdown-encoded text.
+//
+// The simplest invocation of Run takes one argument, input:
+//     output := Run(input)
+// This will parse the input with CommonExtensions enabled and render it with
+// the default HTMLRenderer (with CommonHTMLFlags).
+//
+// Variadic arguments opts can customize the default behavior. Since Markdown
+// type does not contain exported fields, you can not use it directly. Instead,
+// use the With* functions. For example, this will call the most basic
+// functionality, with no extensions:
+//     output := Run(input, WithNoExtensions())
+//
+// You can use any number of With* arguments, even contradicting ones. They
+// will be applied in order of appearance and the latter will override the
+// former:
+//     output := Run(input, WithNoExtensions(), WithExtensions(exts),
+//         WithRenderer(yourRenderer))
+func Run(input []byte, opts ...Option) []byte {
+	r := NewHTMLRenderer(HTMLRendererParameters{
+		Flags: CommonHTMLFlags,
+	})
+	optList := []Option{WithRenderer(r), WithExtensions(CommonExtensions)}
+	optList = append(optList, opts...)
+	parser := New(optList...)
+	ast := parser.Parse(input)
+	var buf bytes.Buffer
+	parser.renderer.RenderHeader(&buf, ast)
+	ast.Walk(func(node *Node, entering bool) WalkStatus {
+		return parser.renderer.RenderNode(&buf, node, entering)
+	})
+	parser.renderer.RenderFooter(&buf, ast)
+	return buf.Bytes()
+}
+
+// Parse is an entry point to the parsing part of Blackfriday. It takes an
+// input markdown document and produces a syntax tree for its contents. This
+// tree can then be rendered with a default or custom renderer, or
+// analyzed/transformed by the caller to whatever non-standard needs they have.
+// The return value is the root node of the syntax tree.
+func (p *Markdown) Parse(input []byte) *Node {
+	p.block(input)
+	// Walk the tree and finish up some of unfinished blocks
+	for p.tip != nil {
+		p.finalize(p.tip)
+	}
+	// Walk the tree again and process inline markdown in each block
+	p.doc.Walk(func(node *Node, entering bool) WalkStatus {
+		if node.Type == Paragraph || node.Type == Heading || node.Type == TableCell {
+			p.inline(node, node.content)
+			node.content = nil
+		}
+		return GoToNext
+	})
+	p.parseRefsToAST()
+	return p.doc
+}
+
+func (p *Markdown) parseRefsToAST() {
+	if p.extensions&Footnotes == 0 || len(p.notes) == 0 {
+		return
+	}
+	p.tip = p.doc
+	block := p.addBlock(List, nil)
+	block.IsFootnotesList = true
+	block.ListFlags = ListTypeOrdered
+	flags := ListItemBeginningOfList
+	// Note: this loop is intentionally explicit, not range-form. This is
+	// because the body of the loop will append nested footnotes to p.notes and
+	// we need to process those late additions. Range form would only walk over
+	// the fixed initial set.
+	for i := 0; i < len(p.notes); i++ {
+		ref := p.notes[i]
+		p.addExistingChild(ref.footnote, 0)
+		block := ref.footnote
+		block.ListFlags = flags | ListTypeOrdered
+		block.RefLink = ref.link
+		if ref.hasBlock {
+			flags |= ListItemContainsBlock
+			p.block(ref.title)
+		} else {
+			p.inline(block, ref.title)
+		}
+		flags &^= ListItemBeginningOfList | ListItemContainsBlock
+	}
+	above := block.Parent
+	finalizeList(block)
+	p.tip = above
+	block.Walk(func(node *Node, entering bool) WalkStatus {
+		if node.Type == Paragraph || node.Type == Heading {
+			p.inline(node, node.content)
+			node.content = nil
+		}
+		return GoToNext
+	})
+}
+
+//
+// Link references
+//
+// This section implements support for references that (usually) appear
+// as footnotes in a document, and can be referenced anywhere in the document.
+// The basic format is:
+//
+//    [1]: http://www.google.com/ "Google"
+//    [2]: http://www.github.com/ "Github"
+//
+// Anywhere in the document, the reference can be linked by referring to its
+// label, i.e., 1 and 2 in this example, as in:
+//
+//    This library is hosted on [Github][2], a git hosting site.
+//
+// Actual footnotes as specified in Pandoc and supported by some other Markdown
+// libraries such as php-markdown are also taken care of. They look like this:
+//
+//    This sentence needs a bit of further explanation.[^note]
+//
+//    [^note]: This is the explanation.
+//
+// Footnotes should be placed at the end of the document in an ordered list.
+// Finally, there are inline footnotes such as:
+//
+//    Inline footnotes^[Also supported.] provide a quick inline explanation,
+//    but are rendered at the bottom of the document.
+//
+
+// reference holds all information necessary for a reference-style links or
+// footnotes.
+//
+// Consider this markdown with reference-style links:
+//
+//     [link][ref]
+//
+//     [ref]: /url/ "tooltip title"
+//
+// It will be ultimately converted to this HTML:
+//
+//     <p><a href=\"/url/\" title=\"title\">link</a></p>
+//
+// And a reference structure will be populated as follows:
+//
+//     p.refs["ref"] = &reference{
+//         link: "/url/",
+//         title: "tooltip title",
+//     }
+//
+// Alternatively, reference can contain information about a footnote. Consider
+// this markdown:
+//
+//     Text needing a footnote.[^a]
+//
+//     [^a]: This is the note
+//
+// A reference structure will be populated as follows:
+//
+//     p.refs["a"] = &reference{
+//         link: "a",
+//         title: "This is the note",
+//         noteID: <some positive int>,
+//     }
+//
+// TODO: As you can see, it begs for splitting into two dedicated structures
+// for refs and for footnotes.
+type reference struct {
+	link     []byte
+	title    []byte
+	noteID   int // 0 if not a footnote ref
+	hasBlock bool
+	footnote *Node // a link to the Item node within a list of footnotes
+
+	text []byte // only gets populated by refOverride feature with Reference.Text
+}
+
+func (r *reference) String() string {
+	return fmt.Sprintf("{link: %q, title: %q, text: %q, noteID: %d, hasBlock: %v}",
+		r.link, r.title, r.text, r.noteID, r.hasBlock)
+}
+
+// Check whether or not data starts with a reference link.
+// If so, it is parsed and stored in the list of references
+// (in the render struct).
+// Returns the number of bytes to skip to move past it,
+// or zero if the first line is not a reference.
+func isReference(p *Markdown, data []byte, tabSize int) int {
+	// up to 3 optional leading spaces
+	if len(data) < 4 {
+		return 0
+	}
+	i := 0
+	for i < 3 && data[i] == ' ' {
+		i++
+	}
+
+	noteID := 0
+
+	// id part: anything but a newline between brackets
+	if data[i] != '[' {
+		return 0
+	}
+	i++
+	if p.extensions&Footnotes != 0 {
+		if i < len(data) && data[i] == '^' {
+			// we can set it to anything here because the proper noteIds will
+			// be assigned later during the second pass. It just has to be != 0
+			noteID = 1
+			i++
+		}
+	}
+	idOffset := i
+	for i < len(data) && data[i] != '\n' && data[i] != '\r' && data[i] != ']' {
+		i++
+	}
+	if i >= len(data) || data[i] != ']' {
+		return 0
+	}
+	idEnd := i
+	// footnotes can have empty ID, like this: [^], but a reference can not be
+	// empty like this: []. Break early if it's not a footnote and there's no ID
+	if noteID == 0 && idOffset == idEnd {
+		return 0
+	}
+	// spacer: colon (space | tab)* newline? (space | tab)*
+	i++
+	if i >= len(data) || data[i] != ':' {
+		return 0
+	}
+	i++
+	for i < len(data) && (data[i] == ' ' || data[i] == '\t') {
+		i++
+	}
+	if i < len(data) && (data[i] == '\n' || data[i] == '\r') {
+		i++
+		if i < len(data) && data[i] == '\n' && data[i-1] == '\r' {
+			i++
+		}
+	}
+	for i < len(data) && (data[i] == ' ' || data[i] == '\t') {
+		i++
+	}
+	if i >= len(data) {
+		return 0
+	}
+
+	var (
+		linkOffset, linkEnd   int
+		titleOffset, titleEnd int
+		lineEnd               int
+		raw                   []byte
+		hasBlock              bool
+	)
+
+	if p.extensions&Footnotes != 0 && noteID != 0 {
+		linkOffset, linkEnd, raw, hasBlock = scanFootnote(p, data, i, tabSize)
+		lineEnd = linkEnd
+	} else {
+		linkOffset, linkEnd, titleOffset, titleEnd, lineEnd = scanLinkRef(p, data, i)
+	}
+	if lineEnd == 0 {
+		return 0
+	}
+
+	// a valid ref has been found
+
+	ref := &reference{
+		noteID:   noteID,
+		hasBlock: hasBlock,
+	}
+
+	if noteID > 0 {
+		// reusing the link field for the id since footnotes don't have links
+		ref.link = data[idOffset:idEnd]
+		// if footnote, it's not really a title, it's the contained text
+		ref.title = raw
+	} else {
+		ref.link = data[linkOffset:linkEnd]
+		ref.title = data[titleOffset:titleEnd]
+	}
+
+	// id matches are case-insensitive
+	id := string(bytes.ToLower(data[idOffset:idEnd]))
+
+	p.refs[id] = ref
+
+	return lineEnd
+}
+
+func scanLinkRef(p *Markdown, data []byte, i int) (linkOffset, linkEnd, titleOffset, titleEnd, lineEnd int) {
+	// link: whitespace-free sequence, optionally between angle brackets
+	if data[i] == '<' {
+		i++
+	}
+	linkOffset = i
+	for i < len(data) && data[i] != ' ' && data[i] != '\t' && data[i] != '\n' && data[i] != '\r' {
+		i++
+	}
+	linkEnd = i
+	if data[linkOffset] == '<' && data[linkEnd-1] == '>' {
+		linkOffset++
+		linkEnd--
+	}
+
+	// optional spacer: (space | tab)* (newline | '\'' | '"' | '(' )
+	for i < len(data) && (data[i] == ' ' || data[i] == '\t') {
+		i++
+	}
+	if i < len(data) && data[i] != '\n' && data[i] != '\r' && data[i] != '\'' && data[i] != '"' && data[i] != '(' {
+		return
+	}
+
+	// compute end-of-line
+	if i >= len(data) || data[i] == '\r' || data[i] == '\n' {
+		lineEnd = i
+	}
+	if i+1 < len(data) && data[i] == '\r' && data[i+1] == '\n' {
+		lineEnd++
+	}
+
+	// optional (space|tab)* spacer after a newline
+	if lineEnd > 0 {
+		i = lineEnd + 1
+		for i < len(data) && (data[i] == ' ' || data[i] == '\t') {
+			i++
+		}
+	}
+
+	// optional title: any non-newline sequence enclosed in '"() alone on its line
+	if i+1 < len(data) && (data[i] == '\'' || data[i] == '"' || data[i] == '(') {
+		i++
+		titleOffset = i
+
+		// look for EOL
+		for i < len(data) && data[i] != '\n' && data[i] != '\r' {
+			i++
+		}
+		if i+1 < len(data) && data[i] == '\n' && data[i+1] == '\r' {
+			titleEnd = i + 1
+		} else {
+			titleEnd = i
+		}
+
+		// step back
+		i--
+		for i > titleOffset && (data[i] == ' ' || data[i] == '\t') {
+			i--
+		}
+		if i > titleOffset && (data[i] == '\'' || data[i] == '"' || data[i] == ')') {
+			lineEnd = titleEnd
+			titleEnd = i
+		}
+	}
+
+	return
+}
+
+// The first bit of this logic is the same as Parser.listItem, but the rest
+// is much simpler. This function simply finds the entire block and shifts it
+// over by one tab if it is indeed a block (just returns the line if it's not).
+// blockEnd is the end of the section in the input buffer, and contents is the
+// extracted text that was shifted over one tab. It will need to be rendered at
+// the end of the document.
+func scanFootnote(p *Markdown, data []byte, i, indentSize int) (blockStart, blockEnd int, contents []byte, hasBlock bool) {
+	if i == 0 || len(data) == 0 {
+		return
+	}
+
+	// skip leading whitespace on first line
+	for i < len(data) && data[i] == ' ' {
+		i++
+	}
+
+	blockStart = i
+
+	// find the end of the line
+	blockEnd = i
+	for i < len(data) && data[i-1] != '\n' {
+		i++
+	}
+
+	// get working buffer
+	var raw bytes.Buffer
+
+	// put the first line into the working buffer
+	raw.Write(data[blockEnd:i])
+	blockEnd = i
+
+	// process the following lines
+	containsBlankLine := false
+
+gatherLines:
+	for blockEnd < len(data) {
+		i++
+
+		// find the end of this line
+		for i < len(data) && data[i-1] != '\n' {
+			i++
+		}
+
+		// if it is an empty line, guess that it is part of this item
+		// and move on to the next line
+		if p.isEmpty(data[blockEnd:i]) > 0 {
+			containsBlankLine = true
+			blockEnd = i
+			continue
+		}
+
+		n := 0
+		if n = isIndented(data[blockEnd:i], indentSize); n == 0 {
+			// this is the end of the block.
+			// we don't want to include this last line in the index.
+			break gatherLines
+		}
+
+		// if there were blank lines before this one, insert a new one now
+		if containsBlankLine {
+			raw.WriteByte('\n')
+			containsBlankLine = false
+		}
+
+		// get rid of that first tab, write to buffer
+		raw.Write(data[blockEnd+n : i])
+		hasBlock = true
+
+		blockEnd = i
+	}
+
+	if data[blockEnd-1] != '\n' {
+		raw.WriteByte('\n')
+	}
+
+	contents = raw.Bytes()
+
+	return
+}
+
+//
+//
+// Miscellaneous helper functions
+//
+//
+
+// Test if a character is a punctuation symbol.
+// Taken from a private function in regexp in the stdlib.
+func ispunct(c byte) bool {
+	for _, r := range []byte("!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~") {
+		if c == r {
+			return true
+		}
+	}
+	return false
+}
+
+// Test if a character is a whitespace character.
+func isspace(c byte) bool {
+	return ishorizontalspace(c) || isverticalspace(c)
+}
+
+// Test if a character is a horizontal whitespace character.
+func ishorizontalspace(c byte) bool {
+	return c == ' ' || c == '\t'
+}
+
+// Test if a character is a vertical character.
+func isverticalspace(c byte) bool {
+	return c == '\n' || c == '\r' || c == '\f' || c == '\v'
+}
+
+// Test if a character is letter.
+func isletter(c byte) bool {
+	return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')
+}
+
+// Test if a character is a letter or a digit.
+// TODO: check when this is looking for ASCII alnum and when it should use unicode
+func isalnum(c byte) bool {
+	return (c >= '0' && c <= '9') || isletter(c)
+}
+
+// Replace tab characters with spaces, aligning to the next TAB_SIZE column.
+// always ends output with a newline
+func expandTabs(out *bytes.Buffer, line []byte, tabSize int) {
+	// first, check for common cases: no tabs, or only tabs at beginning of line
+	i, prefix := 0, 0
+	slowcase := false
+	for i = 0; i < len(line); i++ {
+		if line[i] == '\t' {
+			if prefix == i {
+				prefix++
+			} else {
+				slowcase = true
+				break
+			}
+		}
+	}
+
+	// no need to decode runes if all tabs are at the beginning of the line
+	if !slowcase {
+		for i = 0; i < prefix*tabSize; i++ {
+			out.WriteByte(' ')
+		}
+		out.Write(line[prefix:])
+		return
+	}
+
+	// the slow case: we need to count runes to figure out how
+	// many spaces to insert for each tab
+	column := 0
+	i = 0
+	for i < len(line) {
+		start := i
+		for i < len(line) && line[i] != '\t' {
+			_, size := utf8.DecodeRune(line[i:])
+			i += size
+			column++
+		}
+
+		if i > start {
+			out.Write(line[start:i])
+		}
+
+		if i >= len(line) {
+			break
+		}
+
+		for {
+			out.WriteByte(' ')
+			column++
+			if column%tabSize == 0 {
+				break
+			}
+		}
+
+		i++
+	}
+}
+
+// Find if a line counts as indented or not.
+// Returns number of characters the indent is (0 = not indented).
+func isIndented(data []byte, indentSize int) int {
+	if len(data) == 0 {
+		return 0
+	}
+	if data[0] == '\t' {
+		return 1
+	}
+	if len(data) < indentSize {
+		return 0
+	}
+	for i := 0; i < indentSize; i++ {
+		if data[i] != ' ' {
+			return 0
+		}
+	}
+	return indentSize
+}
+
+// Create a url-safe slug for fragments
+func slugify(in []byte) []byte {
+	if len(in) == 0 {
+		return in
+	}
+	out := make([]byte, 0, len(in))
+	sym := false
+
+	for _, ch := range in {
+		if isalnum(ch) {
+			sym = false
+			out = append(out, ch)
+		} else if sym {
+			continue
+		} else {
+			out = append(out, '-')
+			sym = true
+		}
+	}
+	var a, b int
+	var ch byte
+	for a, ch = range out {
+		if ch != '-' {
+			break
+		}
+	}
+	for b = len(out) - 1; b > 0; b-- {
+		if out[b] != '-' {
+			break
+		}
+	}
+	return out[a : b+1]
+}
diff --git a/vendor/github.com/russross/blackfriday/v2/node.go b/vendor/github.com/russross/blackfriday/v2/node.go
new file mode 100644
index 0000000000..51b9e8c1b5
--- /dev/null
+++ b/vendor/github.com/russross/blackfriday/v2/node.go
@@ -0,0 +1,354 @@
+package blackfriday
+
+import (
+	"bytes"
+	"fmt"
+)
+
+// NodeType specifies a type of a single node of a syntax tree. Usually one
+// node (and its type) corresponds to a single markdown feature, e.g. emphasis
+// or code block.
+type NodeType int
+
+// Constants for identifying different types of nodes. See NodeType.
+const (
+	Document NodeType = iota
+	BlockQuote
+	List
+	Item
+	Paragraph
+	Heading
+	HorizontalRule
+	Emph
+	Strong
+	Del
+	Link
+	Image
+	Text
+	HTMLBlock
+	CodeBlock
+	Softbreak
+	Hardbreak
+	Code
+	HTMLSpan
+	Table
+	TableCell
+	TableHead
+	TableBody
+	TableRow
+)
+
+var nodeTypeNames = []string{
+	Document:       "Document",
+	BlockQuote:     "BlockQuote",
+	List:           "List",
+	Item:           "Item",
+	Paragraph:      "Paragraph",
+	Heading:        "Heading",
+	HorizontalRule: "HorizontalRule",
+	Emph:           "Emph",
+	Strong:         "Strong",
+	Del:            "Del",
+	Link:           "Link",
+	Image:          "Image",
+	Text:           "Text",
+	HTMLBlock:      "HTMLBlock",
+	CodeBlock:      "CodeBlock",
+	Softbreak:      "Softbreak",
+	Hardbreak:      "Hardbreak",
+	Code:           "Code",
+	HTMLSpan:       "HTMLSpan",
+	Table:          "Table",
+	TableCell:      "TableCell",
+	TableHead:      "TableHead",
+	TableBody:      "TableBody",
+	TableRow:       "TableRow",
+}
+
+func (t NodeType) String() string {
+	return nodeTypeNames[t]
+}
+
+// ListData contains fields relevant to a List and Item node type.
+type ListData struct {
+	ListFlags       ListType
+	Tight           bool   // Skip <p>s around list item data if true
+	BulletChar      byte   // '*', '+' or '-' in bullet lists
+	Delimiter       byte   // '.' or ')' after the number in ordered lists
+	RefLink         []byte // If not nil, turns this list item into a footnote item and triggers different rendering
+	IsFootnotesList bool   // This is a list of footnotes
+}
+
+// LinkData contains fields relevant to a Link node type.
+type LinkData struct {
+	Destination []byte // Destination is what goes into a href
+	Title       []byte // Title is the tooltip thing that goes in a title attribute
+	NoteID      int    // NoteID contains a serial number of a footnote, zero if it's not a footnote
+	Footnote    *Node  // If it's a footnote, this is a direct link to the footnote Node. Otherwise nil.
+}
+
+// CodeBlockData contains fields relevant to a CodeBlock node type.
+type CodeBlockData struct {
+	IsFenced    bool   // Specifies whether it's a fenced code block or an indented one
+	Info        []byte // This holds the info string
+	FenceChar   byte
+	FenceLength int
+	FenceOffset int
+}
+
+// TableCellData contains fields relevant to a TableCell node type.
+type TableCellData struct {
+	IsHeader bool           // This tells if it's under the header row
+	Align    CellAlignFlags // This holds the value for align attribute
+}
+
+// HeadingData contains fields relevant to a Heading node type.
+type HeadingData struct {
+	Level        int    // This holds the heading level number
+	HeadingID    string // This might hold heading ID, if present
+	IsTitleblock bool   // Specifies whether it's a title block
+}
+
+// Node is a single element in the abstract syntax tree of the parsed document.
+// It holds connections to the structurally neighboring nodes and, for certain
+// types of nodes, additional information that might be needed when rendering.
+type Node struct {
+	Type       NodeType // Determines the type of the node
+	Parent     *Node    // Points to the parent
+	FirstChild *Node    // Points to the first child, if any
+	LastChild  *Node    // Points to the last child, if any
+	Prev       *Node    // Previous sibling; nil if it's the first child
+	Next       *Node    // Next sibling; nil if it's the last child
+
+	Literal []byte // Text contents of the leaf nodes
+
+	HeadingData   // Populated if Type is Heading
+	ListData      // Populated if Type is List
+	CodeBlockData // Populated if Type is CodeBlock
+	LinkData      // Populated if Type is Link
+	TableCellData // Populated if Type is TableCell
+
+	content []byte // Markdown content of the block nodes
+	open    bool   // Specifies an open block node that has not been finished to process yet
+}
+
+// NewNode allocates a node of a specified type.
+func NewNode(typ NodeType) *Node {
+	return &Node{
+		Type: typ,
+		open: true,
+	}
+}
+
+func (n *Node) String() string {
+	ellipsis := ""
+	snippet := n.Literal
+	if len(snippet) > 16 {
+		snippet = snippet[:16]
+		ellipsis = "..."
+	}
+	return fmt.Sprintf("%s: '%s%s'", n.Type, snippet, ellipsis)
+}
+
+// Unlink removes node 'n' from the tree.
+// It panics if the node is nil.
+func (n *Node) Unlink() {
+	if n.Prev != nil {
+		n.Prev.Next = n.Next
+	} else if n.Parent != nil {
+		n.Parent.FirstChild = n.Next
+	}
+	if n.Next != nil {
+		n.Next.Prev = n.Prev
+	} else if n.Parent != nil {
+		n.Parent.LastChild = n.Prev
+	}
+	n.Parent = nil
+	n.Next = nil
+	n.Prev = nil
+}
+
+// AppendChild adds a node 'child' as a child of 'n'.
+// It panics if either node is nil.
+func (n *Node) AppendChild(child *Node) {
+	child.Unlink()
+	child.Parent = n
+	if n.LastChild != nil {
+		n.LastChild.Next = child
+		child.Prev = n.LastChild
+		n.LastChild = child
+	} else {
+		n.FirstChild = child
+		n.LastChild = child
+	}
+}
+
+// InsertBefore inserts 'sibling' immediately before 'n'.
+// It panics if either node is nil.
+func (n *Node) InsertBefore(sibling *Node) {
+	sibling.Unlink()
+	sibling.Prev = n.Prev
+	if sibling.Prev != nil {
+		sibling.Prev.Next = sibling
+	}
+	sibling.Next = n
+	n.Prev = sibling
+	sibling.Parent = n.Parent
+	if sibling.Prev == nil {
+		sibling.Parent.FirstChild = sibling
+	}
+}
+
+func (n *Node) isContainer() bool {
+	switch n.Type {
+	case Document:
+		fallthrough
+	case BlockQuote:
+		fallthrough
+	case List:
+		fallthrough
+	case Item:
+		fallthrough
+	case Paragraph:
+		fallthrough
+	case Heading:
+		fallthrough
+	case Emph:
+		fallthrough
+	case Strong:
+		fallthrough
+	case Del:
+		fallthrough
+	case Link:
+		fallthrough
+	case Image:
+		fallthrough
+	case Table:
+		fallthrough
+	case TableHead:
+		fallthrough
+	case TableBody:
+		fallthrough
+	case TableRow:
+		fallthrough
+	case TableCell:
+		return true
+	default:
+		return false
+	}
+}
+
+func (n *Node) canContain(t NodeType) bool {
+	if n.Type == List {
+		return t == Item
+	}
+	if n.Type == Document || n.Type == BlockQuote || n.Type == Item {
+		return t != Item
+	}
+	if n.Type == Table {
+		return t == TableHead || t == TableBody
+	}
+	if n.Type == TableHead || n.Type == TableBody {
+		return t == TableRow
+	}
+	if n.Type == TableRow {
+		return t == TableCell
+	}
+	return false
+}
+
+// WalkStatus allows NodeVisitor to have some control over the tree traversal.
+// It is returned from NodeVisitor and different values allow Node.Walk to
+// decide which node to go to next.
+type WalkStatus int
+
+const (
+	// GoToNext is the default traversal of every node.
+	GoToNext WalkStatus = iota
+	// SkipChildren tells walker to skip all children of current node.
+	SkipChildren
+	// Terminate tells walker to terminate the traversal.
+	Terminate
+)
+
+// NodeVisitor is a callback to be called when traversing the syntax tree.
+// Called twice for every node: once with entering=true when the branch is
+// first visited, then with entering=false after all the children are done.
+type NodeVisitor func(node *Node, entering bool) WalkStatus
+
+// Walk is a convenience method that instantiates a walker and starts a
+// traversal of subtree rooted at n.
+func (n *Node) Walk(visitor NodeVisitor) {
+	w := newNodeWalker(n)
+	for w.current != nil {
+		status := visitor(w.current, w.entering)
+		switch status {
+		case GoToNext:
+			w.next()
+		case SkipChildren:
+			w.entering = false
+			w.next()
+		case Terminate:
+			return
+		}
+	}
+}
+
+type nodeWalker struct {
+	current  *Node
+	root     *Node
+	entering bool
+}
+
+func newNodeWalker(root *Node) *nodeWalker {
+	return &nodeWalker{
+		current:  root,
+		root:     root,
+		entering: true,
+	}
+}
+
+func (nw *nodeWalker) next() {
+	if (!nw.current.isContainer() || !nw.entering) && nw.current == nw.root {
+		nw.current = nil
+		return
+	}
+	if nw.entering && nw.current.isContainer() {
+		if nw.current.FirstChild != nil {
+			nw.current = nw.current.FirstChild
+			nw.entering = true
+		} else {
+			nw.entering = false
+		}
+	} else if nw.current.Next == nil {
+		nw.current = nw.current.Parent
+		nw.entering = false
+	} else {
+		nw.current = nw.current.Next
+		nw.entering = true
+	}
+}
+
+func dump(ast *Node) {
+	fmt.Println(dumpString(ast))
+}
+
+func dumpR(ast *Node, depth int) string {
+	if ast == nil {
+		return ""
+	}
+	indent := bytes.Repeat([]byte("\t"), depth)
+	content := ast.Literal
+	if content == nil {
+		content = ast.content
+	}
+	result := fmt.Sprintf("%s%s(%q)\n", indent, ast.Type, content)
+	for n := ast.FirstChild; n != nil; n = n.Next {
+		result += dumpR(n, depth+1)
+	}
+	return result
+}
+
+func dumpString(ast *Node) string {
+	return dumpR(ast, 0)
+}
diff --git a/vendor/github.com/russross/blackfriday/smartypants.go b/vendor/github.com/russross/blackfriday/v2/smartypants.go
similarity index 62%
rename from vendor/github.com/russross/blackfriday/smartypants.go
rename to vendor/github.com/russross/blackfriday/v2/smartypants.go
index eeffa5e1e1..3a220e9424 100644
--- a/vendor/github.com/russross/blackfriday/smartypants.go
+++ b/vendor/github.com/russross/blackfriday/v2/smartypants.go
@@ -17,11 +17,14 @@ package blackfriday
 
 import (
 	"bytes"
+	"io"
 )
 
-type smartypantsData struct {
+// SPRenderer is a struct containing state of a Smartypants renderer.
+type SPRenderer struct {
 	inSingleQuote bool
 	inDoubleQuote bool
+	callbacks     [256]smartCallback
 }
 
 func wordBoundary(c byte) bool {
@@ -39,7 +42,7 @@ func isdigit(c byte) bool {
 	return c >= '0' && c <= '9'
 }
 
-func smartQuoteHelper(out *bytes.Buffer, previousChar byte, nextChar byte, quote byte, isOpen *bool) bool {
+func smartQuoteHelper(out *bytes.Buffer, previousChar byte, nextChar byte, quote byte, isOpen *bool, addNBSP bool) bool {
 	// edge of the buffer is likely to be a tag that we don't get to see,
 	// so we treat it like text sometimes
 
@@ -96,6 +99,12 @@ func smartQuoteHelper(out *bytes.Buffer, previousChar byte, nextChar byte, quote
 		*isOpen = false
 	}
 
+	// Note that with the limited lookahead, this non-breaking
+	// space will also be appended to single double quotes.
+	if addNBSP && !*isOpen {
+		out.WriteString("&nbsp;")
+	}
+
 	out.WriteByte('&')
 	if *isOpen {
 		out.WriteByte('l')
@@ -104,10 +113,15 @@ func smartQuoteHelper(out *bytes.Buffer, previousChar byte, nextChar byte, quote
 	}
 	out.WriteByte(quote)
 	out.WriteString("quo;")
+
+	if addNBSP && *isOpen {
+		out.WriteString("&nbsp;")
+	}
+
 	return true
 }
 
-func smartSingleQuote(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
+func (r *SPRenderer) smartSingleQuote(out *bytes.Buffer, previousChar byte, text []byte) int {
 	if len(text) >= 2 {
 		t1 := tolower(text[1])
 
@@ -116,7 +130,7 @@ func smartSingleQuote(out *bytes.Buffer, smrt *smartypantsData, previousChar byt
 			if len(text) >= 3 {
 				nextChar = text[2]
 			}
-			if smartQuoteHelper(out, previousChar, nextChar, 'd', &smrt.inDoubleQuote) {
+			if smartQuoteHelper(out, previousChar, nextChar, 'd', &r.inDoubleQuote, false) {
 				return 1
 			}
 		}
@@ -141,7 +155,7 @@ func smartSingleQuote(out *bytes.Buffer, smrt *smartypantsData, previousChar byt
 	if len(text) > 1 {
 		nextChar = text[1]
 	}
-	if smartQuoteHelper(out, previousChar, nextChar, 's', &smrt.inSingleQuote) {
+	if smartQuoteHelper(out, previousChar, nextChar, 's', &r.inSingleQuote, false) {
 		return 0
 	}
 
@@ -149,7 +163,7 @@ func smartSingleQuote(out *bytes.Buffer, smrt *smartypantsData, previousChar byt
 	return 0
 }
 
-func smartParens(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
+func (r *SPRenderer) smartParens(out *bytes.Buffer, previousChar byte, text []byte) int {
 	if len(text) >= 3 {
 		t1 := tolower(text[1])
 		t2 := tolower(text[2])
@@ -174,7 +188,7 @@ func smartParens(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, te
 	return 0
 }
 
-func smartDash(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
+func (r *SPRenderer) smartDash(out *bytes.Buffer, previousChar byte, text []byte) int {
 	if len(text) >= 2 {
 		if text[1] == '-' {
 			out.WriteString("&mdash;")
@@ -191,7 +205,7 @@ func smartDash(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text
 	return 0
 }
 
-func smartDashLatex(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
+func (r *SPRenderer) smartDashLatex(out *bytes.Buffer, previousChar byte, text []byte) int {
 	if len(text) >= 3 && text[1] == '-' && text[2] == '-' {
 		out.WriteString("&mdash;")
 		return 2
@@ -205,13 +219,13 @@ func smartDashLatex(out *bytes.Buffer, smrt *smartypantsData, previousChar byte,
 	return 0
 }
 
-func smartAmpVariant(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte, quote byte) int {
+func (r *SPRenderer) smartAmpVariant(out *bytes.Buffer, previousChar byte, text []byte, quote byte, addNBSP bool) int {
 	if bytes.HasPrefix(text, []byte("&quot;")) {
 		nextChar := byte(0)
 		if len(text) >= 7 {
 			nextChar = text[6]
 		}
-		if smartQuoteHelper(out, previousChar, nextChar, quote, &smrt.inDoubleQuote) {
+		if smartQuoteHelper(out, previousChar, nextChar, quote, &r.inDoubleQuote, addNBSP) {
 			return 5
 		}
 	}
@@ -224,15 +238,18 @@ func smartAmpVariant(out *bytes.Buffer, smrt *smartypantsData, previousChar byte
 	return 0
 }
 
-func smartAmp(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
-	return smartAmpVariant(out, smrt, previousChar, text, 'd')
+func (r *SPRenderer) smartAmp(angledQuotes, addNBSP bool) func(*bytes.Buffer, byte, []byte) int {
+	var quote byte = 'd'
+	if angledQuotes {
+		quote = 'a'
+	}
+
+	return func(out *bytes.Buffer, previousChar byte, text []byte) int {
+		return r.smartAmpVariant(out, previousChar, text, quote, addNBSP)
+	}
 }
 
-func smartAmpAngledQuote(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
-	return smartAmpVariant(out, smrt, previousChar, text, 'a')
-}
-
-func smartPeriod(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
+func (r *SPRenderer) smartPeriod(out *bytes.Buffer, previousChar byte, text []byte) int {
 	if len(text) >= 3 && text[1] == '.' && text[2] == '.' {
 		out.WriteString("&hellip;")
 		return 2
@@ -247,13 +264,13 @@ func smartPeriod(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, te
 	return 0
 }
 
-func smartBacktick(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
+func (r *SPRenderer) smartBacktick(out *bytes.Buffer, previousChar byte, text []byte) int {
 	if len(text) >= 2 && text[1] == '`' {
 		nextChar := byte(0)
 		if len(text) >= 3 {
 			nextChar = text[2]
 		}
-		if smartQuoteHelper(out, previousChar, nextChar, 'd', &smrt.inDoubleQuote) {
+		if smartQuoteHelper(out, previousChar, nextChar, 'd', &r.inDoubleQuote, false) {
 			return 1
 		}
 	}
@@ -262,7 +279,7 @@ func smartBacktick(out *bytes.Buffer, smrt *smartypantsData, previousChar byte,
 	return 0
 }
 
-func smartNumberGeneric(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
+func (r *SPRenderer) smartNumberGeneric(out *bytes.Buffer, previousChar byte, text []byte) int {
 	if wordBoundary(previousChar) && previousChar != '/' && len(text) >= 3 {
 		// is it of the form digits/digits(word boundary)?, i.e., \d+/\d+\b
 		// note: check for regular slash (/) or fraction slash (⁄, 0x2044, or 0xe2 81 84 in utf-8)
@@ -304,7 +321,7 @@ func smartNumberGeneric(out *bytes.Buffer, smrt *smartypantsData, previousChar b
 	return 0
 }
 
-func smartNumber(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
+func (r *SPRenderer) smartNumber(out *bytes.Buffer, previousChar byte, text []byte) int {
 	if wordBoundary(previousChar) && previousChar != '/' && len(text) >= 3 {
 		if text[0] == '1' && text[1] == '/' && text[2] == '2' {
 			if len(text) < 4 || wordBoundary(text[3]) && text[3] != '/' {
@@ -332,27 +349,27 @@ func smartNumber(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, te
 	return 0
 }
 
-func smartDoubleQuoteVariant(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte, quote byte) int {
+func (r *SPRenderer) smartDoubleQuoteVariant(out *bytes.Buffer, previousChar byte, text []byte, quote byte) int {
 	nextChar := byte(0)
 	if len(text) > 1 {
 		nextChar = text[1]
 	}
-	if !smartQuoteHelper(out, previousChar, nextChar, quote, &smrt.inDoubleQuote) {
+	if !smartQuoteHelper(out, previousChar, nextChar, quote, &r.inDoubleQuote, false) {
 		out.WriteString("&quot;")
 	}
 
 	return 0
 }
 
-func smartDoubleQuote(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
-	return smartDoubleQuoteVariant(out, smrt, previousChar, text, 'd')
+func (r *SPRenderer) smartDoubleQuote(out *bytes.Buffer, previousChar byte, text []byte) int {
+	return r.smartDoubleQuoteVariant(out, previousChar, text, 'd')
 }
 
-func smartAngledDoubleQuote(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
-	return smartDoubleQuoteVariant(out, smrt, previousChar, text, 'a')
+func (r *SPRenderer) smartAngledDoubleQuote(out *bytes.Buffer, previousChar byte, text []byte) int {
+	return r.smartDoubleQuoteVariant(out, previousChar, text, 'a')
 }
 
-func smartLeftAngle(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int {
+func (r *SPRenderer) smartLeftAngle(out *bytes.Buffer, previousChar byte, text []byte) int {
 	i := 0
 
 	for i < len(text) && text[i] != '>' {
@@ -363,38 +380,78 @@ func smartLeftAngle(out *bytes.Buffer, smrt *smartypantsData, previousChar byte,
 	return i
 }
 
-type smartCallback func(out *bytes.Buffer, smrt *smartypantsData, previousChar byte, text []byte) int
+type smartCallback func(out *bytes.Buffer, previousChar byte, text []byte) int
 
-type smartypantsRenderer [256]smartCallback
+// NewSmartypantsRenderer constructs a Smartypants renderer object.
+func NewSmartypantsRenderer(flags HTMLFlags) *SPRenderer {
+	var (
+		r SPRenderer
 
-func smartypants(flags int) *smartypantsRenderer {
-	r := new(smartypantsRenderer)
-	if flags&HTML_SMARTYPANTS_ANGLED_QUOTES == 0 {
-		r['"'] = smartDoubleQuote
-		r['&'] = smartAmp
-	} else {
-		r['"'] = smartAngledDoubleQuote
-		r['&'] = smartAmpAngledQuote
-	}
-	r['\''] = smartSingleQuote
-	r['('] = smartParens
-	if flags&HTML_SMARTYPANTS_DASHES != 0 {
-		if flags&HTML_SMARTYPANTS_LATEX_DASHES == 0 {
-			r['-'] = smartDash
+		smartAmpAngled      = r.smartAmp(true, false)
+		smartAmpAngledNBSP  = r.smartAmp(true, true)
+		smartAmpRegular     = r.smartAmp(false, false)
+		smartAmpRegularNBSP = r.smartAmp(false, true)
+
+		addNBSP = flags&SmartypantsQuotesNBSP != 0
+	)
+
+	if flags&SmartypantsAngledQuotes == 0 {
+		r.callbacks['"'] = r.smartDoubleQuote
+		if !addNBSP {
+			r.callbacks['&'] = smartAmpRegular
 		} else {
-			r['-'] = smartDashLatex
+			r.callbacks['&'] = smartAmpRegularNBSP
+		}
+	} else {
+		r.callbacks['"'] = r.smartAngledDoubleQuote
+		if !addNBSP {
+			r.callbacks['&'] = smartAmpAngled
+		} else {
+			r.callbacks['&'] = smartAmpAngledNBSP
 		}
 	}
-	r['.'] = smartPeriod
-	if flags&HTML_SMARTYPANTS_FRACTIONS == 0 {
-		r['1'] = smartNumber
-		r['3'] = smartNumber
+	r.callbacks['\''] = r.smartSingleQuote
+	r.callbacks['('] = r.smartParens
+	if flags&SmartypantsDashes != 0 {
+		if flags&SmartypantsLatexDashes == 0 {
+			r.callbacks['-'] = r.smartDash
+		} else {
+			r.callbacks['-'] = r.smartDashLatex
+		}
+	}
+	r.callbacks['.'] = r.smartPeriod
+	if flags&SmartypantsFractions == 0 {
+		r.callbacks['1'] = r.smartNumber
+		r.callbacks['3'] = r.smartNumber
 	} else {
 		for ch := '1'; ch <= '9'; ch++ {
-			r[ch] = smartNumberGeneric
+			r.callbacks[ch] = r.smartNumberGeneric
 		}
 	}
-	r['<'] = smartLeftAngle
-	r['`'] = smartBacktick
-	return r
+	r.callbacks['<'] = r.smartLeftAngle
+	r.callbacks['`'] = r.smartBacktick
+	return &r
+}
+
+// Process is the entry point of the Smartypants renderer.
+func (r *SPRenderer) Process(w io.Writer, text []byte) {
+	mark := 0
+	for i := 0; i < len(text); i++ {
+		if action := r.callbacks[text[i]]; action != nil {
+			if i > mark {
+				w.Write(text[mark:i])
+			}
+			previousChar := byte(0)
+			if i > 0 {
+				previousChar = text[i-1]
+			}
+			var tmp bytes.Buffer
+			i += action(&tmp, previousChar, text[i:])
+			w.Write(tmp.Bytes())
+			mark = i + 1
+		}
+	}
+	if mark < len(text) {
+		w.Write(text[mark:])
+	}
 }
diff --git a/vendor/github.com/shurcooL/sanitized_anchor_name/LICENSE b/vendor/github.com/shurcooL/sanitized_anchor_name/LICENSE
index 5f4e3ed57a..c35c17af98 100644
--- a/vendor/github.com/shurcooL/sanitized_anchor_name/LICENSE
+++ b/vendor/github.com/shurcooL/sanitized_anchor_name/LICENSE
@@ -1,3 +1,5 @@
+MIT License
+
 Copyright (c) 2015 Dmitri Shuralyov
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
@@ -7,13 +9,13 @@ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:
 
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-THE SOFTWARE.
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/vendor/github.com/shurcooL/sanitized_anchor_name/README.md b/vendor/github.com/shurcooL/sanitized_anchor_name/README.md
index cb76fe1a8c..670bf0fe6c 100644
--- a/vendor/github.com/shurcooL/sanitized_anchor_name/README.md
+++ b/vendor/github.com/shurcooL/sanitized_anchor_name/README.md
@@ -1,10 +1,15 @@
-# sanitized_anchor_name [![Build Status](https://travis-ci.org/shurcooL/sanitized_anchor_name.svg?branch=master)](https://travis-ci.org/shurcooL/sanitized_anchor_name) [![GoDoc](https://godoc.org/github.com/shurcooL/sanitized_anchor_name?status.svg)](https://godoc.org/github.com/shurcooL/sanitized_anchor_name)
+sanitized_anchor_name
+=====================
+
+[![Build Status](https://travis-ci.org/shurcooL/sanitized_anchor_name.svg?branch=master)](https://travis-ci.org/shurcooL/sanitized_anchor_name) [![GoDoc](https://godoc.org/github.com/shurcooL/sanitized_anchor_name?status.svg)](https://godoc.org/github.com/shurcooL/sanitized_anchor_name)
 
 Package sanitized_anchor_name provides a func to create sanitized anchor names.
 
-Its logic can be reused by multiple packages to create interoperable anchor names and links to those anchors.
+Its logic can be reused by multiple packages to create interoperable anchor names
+and links to those anchors.
 
-At this time, it does not try to ensure that generated anchor names are unique, that responsibility falls on the caller.
+At this time, it does not try to ensure that generated anchor names
+are unique, that responsibility falls on the caller.
 
 Installation
 ------------
@@ -28,4 +33,4 @@ fmt.Println(anchorName)
 License
 -------
 
-- [MIT License](LICENSE)
+-	[MIT License](LICENSE)
diff --git a/vendor/github.com/shurcooL/sanitized_anchor_name/go.mod b/vendor/github.com/shurcooL/sanitized_anchor_name/go.mod
new file mode 100644
index 0000000000..1e25534759
--- /dev/null
+++ b/vendor/github.com/shurcooL/sanitized_anchor_name/go.mod
@@ -0,0 +1 @@
+module github.com/shurcooL/sanitized_anchor_name
diff --git a/vendor/github.com/shurcooL/sanitized_anchor_name/main.go b/vendor/github.com/shurcooL/sanitized_anchor_name/main.go
index 72a8753509..6a77d12431 100644
--- a/vendor/github.com/shurcooL/sanitized_anchor_name/main.go
+++ b/vendor/github.com/shurcooL/sanitized_anchor_name/main.go
@@ -13,7 +13,7 @@ import "unicode"
 func Create(text string) string {
 	var anchorName []rune
 	var futureDash = false
-	for _, r := range []rune(text) {
+	for _, r := range text {
 		switch {
 		case unicode.IsLetter(r) || unicode.IsNumber(r):
 			if futureDash && len(anchorName) > 0 {
diff --git a/vendor/github.com/spf13/cobra/README.md b/vendor/github.com/spf13/cobra/README.md
index 851fcc087c..9d79934260 100644
--- a/vendor/github.com/spf13/cobra/README.md
+++ b/vendor/github.com/spf13/cobra/README.md
@@ -2,29 +2,35 @@
 
 Cobra is both a library for creating powerful modern CLI applications as well as a program to generate applications and command files.
 
-Many of the most widely used Go projects are built using Cobra including:
-
-* [Kubernetes](http://kubernetes.io/)
-* [Hugo](http://gohugo.io)
-* [rkt](https://github.com/coreos/rkt)
-* [etcd](https://github.com/coreos/etcd)
-* [Moby (former Docker)](https://github.com/moby/moby)
-* [Docker (distribution)](https://github.com/docker/distribution)
-* [OpenShift](https://www.openshift.com/)
-* [Delve](https://github.com/derekparker/delve)
-* [GopherJS](http://www.gopherjs.org/)
-* [CockroachDB](http://www.cockroachlabs.com/)
-* [Bleve](http://www.blevesearch.com/)
-* [ProjectAtomic (enterprise)](http://www.projectatomic.io/)
-* [GiantSwarm's swarm](https://github.com/giantswarm/cli)
-* [Nanobox](https://github.com/nanobox-io/nanobox)/[Nanopack](https://github.com/nanopack)
-* [rclone](http://rclone.org/)
-* [nehm](https://github.com/bogem/nehm)
-* [Pouch](https://github.com/alibaba/pouch)
+Many of the most widely used Go projects are built using Cobra, such as:
+[Kubernetes](http://kubernetes.io/),
+[Hugo](http://gohugo.io),
+[rkt](https://github.com/coreos/rkt),
+[etcd](https://github.com/coreos/etcd),
+[Moby (former Docker)](https://github.com/moby/moby),
+[Docker (distribution)](https://github.com/docker/distribution),
+[OpenShift](https://www.openshift.com/),
+[Delve](https://github.com/derekparker/delve),
+[GopherJS](http://www.gopherjs.org/),
+[CockroachDB](http://www.cockroachlabs.com/),
+[Bleve](http://www.blevesearch.com/),
+[ProjectAtomic (enterprise)](http://www.projectatomic.io/),
+[Giant Swarm's gsctl](https://github.com/giantswarm/gsctl),
+[Nanobox](https://github.com/nanobox-io/nanobox)/[Nanopack](https://github.com/nanopack),
+[rclone](http://rclone.org/),
+[nehm](https://github.com/bogem/nehm),
+[Pouch](https://github.com/alibaba/pouch),
+[Istio](https://istio.io),
+[Prototool](https://github.com/uber/prototool),
+[mattermost-server](https://github.com/mattermost/mattermost-server),
+[Gardener](https://github.com/gardener/gardenctl),
+[Linkerd](https://linkerd.io/),
+[Github CLI](https://github.com/cli/cli)
+etc.
 
 [![Build Status](https://travis-ci.org/spf13/cobra.svg "Travis CI status")](https://travis-ci.org/spf13/cobra)
-[![CircleCI status](https://circleci.com/gh/spf13/cobra.png?circle-token=:circle-token "CircleCI status")](https://circleci.com/gh/spf13/cobra)
 [![GoDoc](https://godoc.org/github.com/spf13/cobra?status.svg)](https://godoc.org/github.com/spf13/cobra)
+[![Go Report Card](https://goreportcard.com/badge/github.com/spf13/cobra)](https://goreportcard.com/report/github.com/spf13/cobra)
 
 # Table of Contents
 
@@ -45,6 +51,7 @@ Many of the most widely used Go projects are built using Cobra including:
   * [Suggestions when "unknown command" happens](#suggestions-when-unknown-command-happens)
   * [Generating documentation for your command](#generating-documentation-for-your-command)
   * [Generating bash completions](#generating-bash-completions)
+  * [Generating zsh completions](#generating-zsh-completions)
 - [Contributing](#contributing)
 - [License](#license)
 
@@ -152,9 +159,6 @@ In a Cobra app, typically the main.go file is very bare. It serves one purpose:
 package main
 
 import (
-  "fmt"
-  "os"
-
   "{pathToYourApp}/cmd"
 )
 
@@ -206,51 +210,78 @@ You will additionally define flags and handle configuration in your init() funct
 For example cmd/root.go:
 
 ```go
-import (
-  "fmt"
-  "os"
+package cmd
 
-  homedir "github.com/mitchellh/go-homedir"
-  "github.com/spf13/cobra"
-  "github.com/spf13/viper"
+import (
+	"fmt"
+	"os"
+
+	homedir "github.com/mitchellh/go-homedir"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
 )
 
+var (
+	// Used for flags.
+	cfgFile     string
+	userLicense string
+
+	rootCmd = &cobra.Command{
+		Use:   "cobra",
+		Short: "A generator for Cobra based Applications",
+		Long: `Cobra is a CLI library for Go that empowers applications.
+This application is a tool to generate the needed files
+to quickly create a Cobra application.`,
+	}
+)
+
+// Execute executes the root command.
+func Execute() error {
+	return rootCmd.Execute()
+}
+
 func init() {
-  cobra.OnInitialize(initConfig)
-  rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.cobra.yaml)")
-  rootCmd.PersistentFlags().StringVarP(&projectBase, "projectbase", "b", "", "base project directory eg. github.com/spf13/")
-  rootCmd.PersistentFlags().StringP("author", "a", "YOUR NAME", "Author name for copyright attribution")
-  rootCmd.PersistentFlags().StringVarP(&userLicense, "license", "l", "", "Name of license for the project (can provide `licensetext` in config)")
-  rootCmd.PersistentFlags().Bool("viper", true, "Use Viper for configuration")
-  viper.BindPFlag("author", rootCmd.PersistentFlags().Lookup("author"))
-  viper.BindPFlag("projectbase", rootCmd.PersistentFlags().Lookup("projectbase"))
-  viper.BindPFlag("useViper", rootCmd.PersistentFlags().Lookup("viper"))
-  viper.SetDefault("author", "NAME HERE <EMAIL ADDRESS>")
-  viper.SetDefault("license", "apache")
+	cobra.OnInitialize(initConfig)
+
+	rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.cobra.yaml)")
+	rootCmd.PersistentFlags().StringP("author", "a", "YOUR NAME", "author name for copyright attribution")
+	rootCmd.PersistentFlags().StringVarP(&userLicense, "license", "l", "", "name of license for the project")
+	rootCmd.PersistentFlags().Bool("viper", true, "use Viper for configuration")
+	viper.BindPFlag("author", rootCmd.PersistentFlags().Lookup("author"))
+	viper.BindPFlag("useViper", rootCmd.PersistentFlags().Lookup("viper"))
+	viper.SetDefault("author", "NAME HERE <EMAIL ADDRESS>")
+	viper.SetDefault("license", "apache")
+
+	rootCmd.AddCommand(addCmd)
+	rootCmd.AddCommand(initCmd)
+}
+
+func er(msg interface{}) {
+	fmt.Println("Error:", msg)
+	os.Exit(1)
 }
 
 func initConfig() {
-  // Don't forget to read config either from cfgFile or from home directory!
-  if cfgFile != "" {
-    // Use config file from the flag.
-    viper.SetConfigFile(cfgFile)
-  } else {
-    // Find home directory.
-    home, err := homedir.Dir()
-    if err != nil {
-      fmt.Println(err)
-      os.Exit(1)
-    }
+	if cfgFile != "" {
+		// Use config file from the flag.
+		viper.SetConfigFile(cfgFile)
+	} else {
+		// Find home directory.
+		home, err := homedir.Dir()
+		if err != nil {
+			er(err)
+		}
 
-    // Search config in home directory with name ".cobra" (without extension).
-    viper.AddConfigPath(home)
-    viper.SetConfigName(".cobra")
-  }
+		// Search config in home directory with name ".cobra" (without extension).
+		viper.AddConfigPath(home)
+		viper.SetConfigName(".cobra")
+	}
 
-  if err := viper.ReadInConfig(); err != nil {
-    fmt.Println("Can't read config:", err)
-    os.Exit(1)
-  }
+	viper.AutomaticEnv()
+
+	if err := viper.ReadInConfig(); err == nil {
+		fmt.Println("Using config file:", viper.ConfigFileUsed())
+	}
 }
 ```
 
@@ -265,9 +296,6 @@ In a Cobra app, typically the main.go file is very bare. It serves, one purpose,
 package main
 
 import (
-  "fmt"
-  "os"
-
   "{pathToYourApp}/cmd"
 )
 
@@ -339,7 +367,7 @@ rootCmd.PersistentFlags().BoolVarP(&Verbose, "verbose", "v", false, "verbose out
 A flag can also be assigned locally which will only apply to that specific command.
 
 ```go
-rootCmd.Flags().StringVarP(&Source, "source", "s", "", "Source directory to read from")
+localCmd.Flags().StringVarP(&Source, "source", "s", "", "Source directory to read from")
 ```
 
 ### Local Flag on Parent Commands
@@ -395,6 +423,7 @@ The following validators are built in:
 - `MinimumNArgs(int)` - the command will report an error if there are not at least N positional args.
 - `MaximumNArgs(int)` - the command will report an error if there are more than N positional args.
 - `ExactArgs(int)` - the command will report an error if there are not exactly N positional args.
+- `ExactValidArgs(int)` - the command will report an error if there are not exactly N positional args OR if there are any positional args that are not in the `ValidArgs` field of `Command`
 - `RangeArgs(min, max)` - the command will report an error if the number of args is not between the minimum and maximum number of expected args.
 
 An example of setting the custom validator:
@@ -404,7 +433,7 @@ var cmd = &cobra.Command{
   Short: "hello",
   Args: func(cmd *cobra.Command, args []string) error {
     if len(args) < 1 {
-      return errors.New("requires at least one arg")
+      return errors.New("requires a color argument")
     }
     if myapp.IsValidColor(args[0]) {
       return nil
@@ -459,12 +488,12 @@ For many years people have printed back to the screen.`,
 Echo works a lot like print, except it has a child command.`,
     Args: cobra.MinimumNArgs(1),
     Run: func(cmd *cobra.Command, args []string) {
-      fmt.Println("Print: " + strings.Join(args, " "))
+      fmt.Println("Echo: " + strings.Join(args, " "))
     },
   }
 
   var cmdTimes = &cobra.Command{
-    Use:   "times [# times] [string to echo]",
+    Use:   "times [string to echo]",
     Short: "Echo anything to the screen more times",
     Long: `echo things multiple times back to the user by providing
 a count and a string.`,
@@ -721,6 +750,11 @@ Cobra can generate documentation based on subcommands, flags, etc. in the follow
 
 Cobra can generate a bash-completion file. If you add more information to your command, these completions can be amazingly powerful and flexible.  Read more about it in [Bash Completions](bash_completions.md).
 
+## Generating zsh completions
+
+Cobra can generate zsh-completion file. Read more about it in
+[Zsh Completions](zsh_completions.md).
+
 # Contributing
 
 1. Fork it
diff --git a/vendor/github.com/spf13/cobra/args.go b/vendor/github.com/spf13/cobra/args.go
index a5d8a9273e..70e9b26291 100644
--- a/vendor/github.com/spf13/cobra/args.go
+++ b/vendor/github.com/spf13/cobra/args.go
@@ -2,6 +2,7 @@ package cobra
 
 import (
 	"fmt"
+	"strings"
 )
 
 type PositionalArgs func(cmd *Command, args []string) error
@@ -34,8 +35,15 @@ func NoArgs(cmd *Command, args []string) error {
 // OnlyValidArgs returns an error if any args are not in the list of ValidArgs.
 func OnlyValidArgs(cmd *Command, args []string) error {
 	if len(cmd.ValidArgs) > 0 {
+		// Remove any description that may be included in ValidArgs.
+		// A description is following a tab character.
+		var validArgs []string
+		for _, v := range cmd.ValidArgs {
+			validArgs = append(validArgs, strings.Split(v, "\t")[0])
+		}
+
 		for _, v := range args {
-			if !stringInSlice(v, cmd.ValidArgs) {
+			if !stringInSlice(v, validArgs) {
 				return fmt.Errorf("invalid argument %q for %q%s", v, cmd.CommandPath(), cmd.findSuggestions(args[0]))
 			}
 		}
@@ -78,6 +86,18 @@ func ExactArgs(n int) PositionalArgs {
 	}
 }
 
+// ExactValidArgs returns an error if
+// there are not exactly N positional args OR
+// there are any positional args that are not in the `ValidArgs` field of `Command`
+func ExactValidArgs(n int) PositionalArgs {
+	return func(cmd *Command, args []string) error {
+		if err := ExactArgs(n)(cmd, args); err != nil {
+			return err
+		}
+		return OnlyValidArgs(cmd, args)
+	}
+}
+
 // RangeArgs returns an error if the number of args is not within the expected range.
 func RangeArgs(min int, max int) PositionalArgs {
 	return func(cmd *Command, args []string) error {
diff --git a/vendor/github.com/spf13/cobra/bash_completions.go b/vendor/github.com/spf13/cobra/bash_completions.go
index 8fa8f486fa..1e27188c3d 100644
--- a/vendor/github.com/spf13/cobra/bash_completions.go
+++ b/vendor/github.com/spf13/cobra/bash_completions.go
@@ -58,9 +58,71 @@ __%[1]s_contains_word()
     return 1
 }
 
+__%[1]s_handle_go_custom_completion()
+{
+    __%[1]s_debug "${FUNCNAME[0]}: cur is ${cur}, words[*] is ${words[*]}, #words[@] is ${#words[@]}"
+
+    local out requestComp lastParam lastChar comp directive args
+
+    # Prepare the command to request completions for the program.
+    # Calling ${words[0]} instead of directly %[1]s allows to handle aliases
+    args=("${words[@]:1}")
+    requestComp="${words[0]} %[2]s ${args[*]}"
+
+    lastParam=${words[$((${#words[@]}-1))]}
+    lastChar=${lastParam:$((${#lastParam}-1)):1}
+    __%[1]s_debug "${FUNCNAME[0]}: lastParam ${lastParam}, lastChar ${lastChar}"
+
+    if [ -z "${cur}" ] && [ "${lastChar}" != "=" ]; then
+        # If the last parameter is complete (there is a space following it)
+        # We add an extra empty parameter so we can indicate this to the go method.
+        __%[1]s_debug "${FUNCNAME[0]}: Adding extra empty parameter"
+        requestComp="${requestComp} \"\""
+    fi
+
+    __%[1]s_debug "${FUNCNAME[0]}: calling ${requestComp}"
+    # Use eval to handle any environment variables and such
+    out=$(eval "${requestComp}" 2>/dev/null)
+
+    # Extract the directive integer at the very end of the output following a colon (:)
+    directive=${out##*:}
+    # Remove the directive
+    out=${out%%:*}
+    if [ "${directive}" = "${out}" ]; then
+        # There is not directive specified
+        directive=0
+    fi
+    __%[1]s_debug "${FUNCNAME[0]}: the completion directive is: ${directive}"
+    __%[1]s_debug "${FUNCNAME[0]}: the completions are: ${out[*]}"
+
+    if [ $((directive & %[3]d)) -ne 0 ]; then
+        # Error code.  No completion.
+        __%[1]s_debug "${FUNCNAME[0]}: received error from custom completion go code"
+        return
+    else
+        if [ $((directive & %[4]d)) -ne 0 ]; then
+            if [[ $(type -t compopt) = "builtin" ]]; then
+                __%[1]s_debug "${FUNCNAME[0]}: activating no space"
+                compopt -o nospace
+            fi
+        fi
+        if [ $((directive & %[5]d)) -ne 0 ]; then
+            if [[ $(type -t compopt) = "builtin" ]]; then
+                __%[1]s_debug "${FUNCNAME[0]}: activating no file completion"
+                compopt +o default
+            fi
+        fi
+
+        while IFS='' read -r comp; do
+            COMPREPLY+=("$comp")
+        done < <(compgen -W "${out[*]}" -- "$cur")
+    fi
+}
+
 __%[1]s_handle_reply()
 {
     __%[1]s_debug "${FUNCNAME[0]}"
+    local comp
     case $cur in
         -*)
             if [[ $(type -t compopt) = "builtin" ]]; then
@@ -72,7 +134,9 @@ __%[1]s_handle_reply()
             else
                 allflags=("${flags[*]} ${two_word_flags[*]}")
             fi
-            COMPREPLY=( $(compgen -W "${allflags[*]}" -- "$cur") )
+            while IFS='' read -r comp; do
+                COMPREPLY+=("$comp")
+            done < <(compgen -W "${allflags[*]}" -- "$cur")
             if [[ $(type -t compopt) = "builtin" ]]; then
                 [[ "${COMPREPLY[0]}" == *= ]] || compopt +o nospace
             fi
@@ -118,18 +182,32 @@ __%[1]s_handle_reply()
     completions=("${commands[@]}")
     if [[ ${#must_have_one_noun[@]} -ne 0 ]]; then
         completions=("${must_have_one_noun[@]}")
+    elif [[ -n "${has_completion_function}" ]]; then
+        # if a go completion function is provided, defer to that function
+        completions=()
+        __%[1]s_handle_go_custom_completion
     fi
     if [[ ${#must_have_one_flag[@]} -ne 0 ]]; then
         completions+=("${must_have_one_flag[@]}")
     fi
-    COMPREPLY=( $(compgen -W "${completions[*]}" -- "$cur") )
+    while IFS='' read -r comp; do
+        COMPREPLY+=("$comp")
+    done < <(compgen -W "${completions[*]}" -- "$cur")
 
     if [[ ${#COMPREPLY[@]} -eq 0 && ${#noun_aliases[@]} -gt 0 && ${#must_have_one_noun[@]} -ne 0 ]]; then
-        COMPREPLY=( $(compgen -W "${noun_aliases[*]}" -- "$cur") )
+        while IFS='' read -r comp; do
+            COMPREPLY+=("$comp")
+        done < <(compgen -W "${noun_aliases[*]}" -- "$cur")
     fi
 
     if [[ ${#COMPREPLY[@]} -eq 0 ]]; then
-        declare -F __custom_func >/dev/null && __custom_func
+		if declare -F __%[1]s_custom_func >/dev/null; then
+			# try command name qualified custom func
+			__%[1]s_custom_func
+		else
+			# otherwise fall back to unqualified for compatibility
+			declare -F __custom_func >/dev/null && __custom_func
+		fi
     fi
 
     # available in bash-completion >= 2, not always present on macOS
@@ -154,7 +232,7 @@ __%[1]s_handle_filename_extension_flag()
 __%[1]s_handle_subdirs_in_dir_flag()
 {
     local dir="$1"
-    pushd "${dir}" >/dev/null 2>&1 && _filedir -d && popd >/dev/null 2>&1
+    pushd "${dir}" >/dev/null 2>&1 && _filedir -d && popd >/dev/null 2>&1 || return
 }
 
 __%[1]s_handle_flag()
@@ -193,7 +271,8 @@ __%[1]s_handle_flag()
     fi
 
     # skip the argument to a two word flag
-    if __%[1]s_contains_word "${words[c]}" "${two_word_flags[@]}"; then
+    if [[ ${words[c]} != *"="* ]] && __%[1]s_contains_word "${words[c]}" "${two_word_flags[@]}"; then
+			  __%[1]s_debug "${FUNCNAME[0]}: found a flag ${words[c]}, skip the next argument"
         c=$((c+1))
         # if we are looking for a flags value, don't show commands
         if [[ $c -eq $cword ]]; then
@@ -265,7 +344,7 @@ __%[1]s_handle_word()
     __%[1]s_handle_word
 }
 
-`, name))
+`, name, ShellCompNoDescRequestCmd, ShellCompDirectiveError, ShellCompDirectiveNoSpace, ShellCompDirectiveNoFileComp))
 }
 
 func writePostscript(buf *bytes.Buffer, name string) {
@@ -290,6 +369,7 @@ func writePostscript(buf *bytes.Buffer, name string) {
     local commands=("%[1]s")
     local must_have_one_flag=()
     local must_have_one_noun=()
+    local has_completion_function
     local last_command
     local nouns=()
 
@@ -373,6 +453,10 @@ func writeFlag(buf *bytes.Buffer, flag *pflag.Flag, cmd *Command) {
 	}
 	format += "\")\n"
 	buf.WriteString(fmt.Sprintf(format, name))
+	if len(flag.NoOptDefVal) == 0 {
+		format = "    two_word_flags+=(\"--%s\")\n"
+		buf.WriteString(fmt.Sprintf(format, name))
+	}
 	writeFlagHandler(buf, "--"+name, flag.Annotations, cmd)
 }
 
@@ -386,7 +470,22 @@ func writeLocalNonPersistentFlag(buf *bytes.Buffer, flag *pflag.Flag) {
 	buf.WriteString(fmt.Sprintf(format, name))
 }
 
+// Setup annotations for go completions for registered flags
+func prepareCustomAnnotationsForFlags(cmd *Command) {
+	for flag := range flagCompletionFunctions {
+		// Make sure the completion script calls the __*_go_custom_completion function for
+		// every registered flag.  We need to do this here (and not when the flag was registered
+		// for completion) so that we can know the root command name for the prefix
+		// of __<prefix>_go_custom_completion
+		if flag.Annotations == nil {
+			flag.Annotations = map[string][]string{}
+		}
+		flag.Annotations[BashCompCustom] = []string{fmt.Sprintf("__%[1]s_handle_go_custom_completion", cmd.Root().Name())}
+	}
+}
+
 func writeFlags(buf *bytes.Buffer, cmd *Command) {
+	prepareCustomAnnotationsForFlags(cmd)
 	buf.WriteString(`    flags=()
     two_word_flags=()
     local_nonpersistent_flags=()
@@ -449,8 +548,14 @@ func writeRequiredNouns(buf *bytes.Buffer, cmd *Command) {
 	buf.WriteString("    must_have_one_noun=()\n")
 	sort.Sort(sort.StringSlice(cmd.ValidArgs))
 	for _, value := range cmd.ValidArgs {
+		// Remove any description that may be included following a tab character.
+		// Descriptions are not supported by bash completion.
+		value = strings.Split(value, "\t")[0]
 		buf.WriteString(fmt.Sprintf("    must_have_one_noun+=(%q)\n", value))
 	}
+	if cmd.ValidArgsFunction != nil {
+		buf.WriteString("    has_completion_function=1\n")
+	}
 }
 
 func writeCmdAliases(buf *bytes.Buffer, cmd *Command) {
@@ -534,51 +639,3 @@ func (c *Command) GenBashCompletionFile(filename string) error {
 
 	return c.GenBashCompletion(outFile)
 }
-
-// MarkFlagRequired adds the BashCompOneRequiredFlag annotation to the named flag if it exists,
-// and causes your command to report an error if invoked without the flag.
-func (c *Command) MarkFlagRequired(name string) error {
-	return MarkFlagRequired(c.Flags(), name)
-}
-
-// MarkPersistentFlagRequired adds the BashCompOneRequiredFlag annotation to the named persistent flag if it exists,
-// and causes your command to report an error if invoked without the flag.
-func (c *Command) MarkPersistentFlagRequired(name string) error {
-	return MarkFlagRequired(c.PersistentFlags(), name)
-}
-
-// MarkFlagRequired adds the BashCompOneRequiredFlag annotation to the named flag if it exists,
-// and causes your command to report an error if invoked without the flag.
-func MarkFlagRequired(flags *pflag.FlagSet, name string) error {
-	return flags.SetAnnotation(name, BashCompOneRequiredFlag, []string{"true"})
-}
-
-// MarkFlagFilename adds the BashCompFilenameExt annotation to the named flag, if it exists.
-// Generated bash autocompletion will select filenames for the flag, limiting to named extensions if provided.
-func (c *Command) MarkFlagFilename(name string, extensions ...string) error {
-	return MarkFlagFilename(c.Flags(), name, extensions...)
-}
-
-// MarkFlagCustom adds the BashCompCustom annotation to the named flag, if it exists.
-// Generated bash autocompletion will call the bash function f for the flag.
-func (c *Command) MarkFlagCustom(name string, f string) error {
-	return MarkFlagCustom(c.Flags(), name, f)
-}
-
-// MarkPersistentFlagFilename adds the BashCompFilenameExt annotation to the named persistent flag, if it exists.
-// Generated bash autocompletion will select filenames for the flag, limiting to named extensions if provided.
-func (c *Command) MarkPersistentFlagFilename(name string, extensions ...string) error {
-	return MarkFlagFilename(c.PersistentFlags(), name, extensions...)
-}
-
-// MarkFlagFilename adds the BashCompFilenameExt annotation to the named flag in the flag set, if it exists.
-// Generated bash autocompletion will select filenames for the flag, limiting to named extensions if provided.
-func MarkFlagFilename(flags *pflag.FlagSet, name string, extensions ...string) error {
-	return flags.SetAnnotation(name, BashCompFilenameExt, extensions)
-}
-
-// MarkFlagCustom adds the BashCompCustom annotation to the named flag in the flag set, if it exists.
-// Generated bash autocompletion will call the bash function f for the flag.
-func MarkFlagCustom(flags *pflag.FlagSet, name string, f string) error {
-	return flags.SetAnnotation(name, BashCompCustom, []string{f})
-}
diff --git a/vendor/github.com/spf13/cobra/cobra.go b/vendor/github.com/spf13/cobra/cobra.go
index 7010fd15b7..d01becc8fa 100644
--- a/vendor/github.com/spf13/cobra/cobra.go
+++ b/vendor/github.com/spf13/cobra/cobra.go
@@ -23,6 +23,7 @@ import (
 	"strconv"
 	"strings"
 	"text/template"
+	"time"
 	"unicode"
 )
 
@@ -51,11 +52,17 @@ var EnableCommandSorting = true
 // if the CLI is started from explorer.exe.
 // To disable the mousetrap, just set this variable to blank string ("").
 // Works only on Microsoft Windows.
-var MousetrapHelpText string = `This is a command line tool.
+var MousetrapHelpText = `This is a command line tool.
 
 You need to open cmd.exe and run it from there.
 `
 
+// MousetrapDisplayDuration controls how long the MousetrapHelpText message is displayed on Windows
+// if the CLI is started from explorer.exe. Set to 0 to wait for the return key to be pressed.
+// To disable the mousetrap, just set MousetrapHelpText to blank string ("").
+// Works only on Microsoft Windows.
+var MousetrapDisplayDuration = 5 * time.Second
+
 // AddTemplateFunc adds a template function that's available to Usage and Help
 // template generation.
 func AddTemplateFunc(name string, tmplFunc interface{}) {
diff --git a/vendor/github.com/spf13/cobra/command.go b/vendor/github.com/spf13/cobra/command.go
index 34d1bf3671..88e6ed77d0 100644
--- a/vendor/github.com/spf13/cobra/command.go
+++ b/vendor/github.com/spf13/cobra/command.go
@@ -17,6 +17,7 @@ package cobra
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"io"
 	"os"
@@ -56,6 +57,10 @@ type Command struct {
 
 	// ValidArgs is list of all valid non-flag arguments that are accepted in bash completions
 	ValidArgs []string
+	// ValidArgsFunction is an optional function that provides valid non-flag arguments for bash completion.
+	// It is a dynamic version of using ValidArgs.
+	// Only one of ValidArgs and ValidArgsFunction can be used for a command.
+	ValidArgsFunction func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective)
 
 	// Expected arguments
 	Args PositionalArgs
@@ -80,7 +85,8 @@ type Command struct {
 
 	// Version defines the version for this command. If this value is non-empty and the command does not
 	// define a "version" flag, a "version" boolean flag will be added to the command and, if specified,
-	// will print content of the "Version" variable.
+	// will print content of the "Version" variable. A shorthand "v" flag will also be added if the
+	// command does not define one.
 	Version string
 
 	// The *Run functions are executed in the following order:
@@ -140,9 +146,11 @@ type Command struct {
 	// TraverseChildren parses flags on all parents before executing child command.
 	TraverseChildren bool
 
-	//FParseErrWhitelist flag parse errors to be ignored
+	// FParseErrWhitelist flag parse errors to be ignored
 	FParseErrWhitelist FParseErrWhitelist
 
+	ctx context.Context
+
 	// commands is the list of commands supported by this program.
 	commands []*Command
 	// parent is a parent command for this command.
@@ -177,8 +185,6 @@ type Command struct {
 	// that we can use on every pflag set and children commands
 	globNormFunc func(f *flag.FlagSet, name string) flag.NormalizedName
 
-	// output is an output writer defined by user.
-	output io.Writer
 	// usageFunc is usage func defined by user.
 	usageFunc func(*Command) error
 	// usageTemplate is usage template defined by user.
@@ -195,6 +201,19 @@ type Command struct {
 	helpCommand *Command
 	// versionTemplate is the version template defined by user.
 	versionTemplate string
+
+	// inReader is a reader defined by the user that replaces stdin
+	inReader io.Reader
+	// outWriter is a writer defined by the user that replaces stdout
+	outWriter io.Writer
+	// errWriter is a writer defined by the user that replaces stderr
+	errWriter io.Writer
+}
+
+// Context returns underlying command context. If command wasn't
+// executed with ExecuteContext Context returns Background context.
+func (c *Command) Context() context.Context {
+	return c.ctx
 }
 
 // SetArgs sets arguments for the command. It is set to os.Args[1:] by default, if desired, can be overridden
@@ -205,8 +224,28 @@ func (c *Command) SetArgs(a []string) {
 
 // SetOutput sets the destination for usage and error messages.
 // If output is nil, os.Stderr is used.
+// Deprecated: Use SetOut and/or SetErr instead
 func (c *Command) SetOutput(output io.Writer) {
-	c.output = output
+	c.outWriter = output
+	c.errWriter = output
+}
+
+// SetOut sets the destination for usage messages.
+// If newOut is nil, os.Stdout is used.
+func (c *Command) SetOut(newOut io.Writer) {
+	c.outWriter = newOut
+}
+
+// SetErr sets the destination for error messages.
+// If newErr is nil, os.Stderr is used.
+func (c *Command) SetErr(newErr io.Writer) {
+	c.errWriter = newErr
+}
+
+// SetIn sets the source for input data
+// If newIn is nil, os.Stdin is used.
+func (c *Command) SetIn(newIn io.Reader) {
+	c.inReader = newIn
 }
 
 // SetUsageFunc sets usage function. Usage can be defined by application.
@@ -267,9 +306,19 @@ func (c *Command) OutOrStderr() io.Writer {
 	return c.getOut(os.Stderr)
 }
 
+// ErrOrStderr returns output to stderr
+func (c *Command) ErrOrStderr() io.Writer {
+	return c.getErr(os.Stderr)
+}
+
+// InOrStdin returns input to stdin
+func (c *Command) InOrStdin() io.Reader {
+	return c.getIn(os.Stdin)
+}
+
 func (c *Command) getOut(def io.Writer) io.Writer {
-	if c.output != nil {
-		return c.output
+	if c.outWriter != nil {
+		return c.outWriter
 	}
 	if c.HasParent() {
 		return c.parent.getOut(def)
@@ -277,6 +326,26 @@ func (c *Command) getOut(def io.Writer) io.Writer {
 	return def
 }
 
+func (c *Command) getErr(def io.Writer) io.Writer {
+	if c.errWriter != nil {
+		return c.errWriter
+	}
+	if c.HasParent() {
+		return c.parent.getErr(def)
+	}
+	return def
+}
+
+func (c *Command) getIn(def io.Reader) io.Reader {
+	if c.inReader != nil {
+		return c.inReader
+	}
+	if c.HasParent() {
+		return c.parent.getIn(def)
+	}
+	return def
+}
+
 // UsageFunc returns either the function set by SetUsageFunc for this command
 // or a parent, or it returns a default usage function.
 func (c *Command) UsageFunc() (f func(*Command) error) {
@@ -314,6 +383,8 @@ func (c *Command) HelpFunc() func(*Command, []string) {
 	}
 	return func(c *Command, a []string) {
 		c.mergePersistentFlags()
+		// The help should be sent to stdout
+		// See https://github.com/spf13/cobra/issues/1002
 		err := tmpl(c.OutOrStdout(), c.HelpTemplate(), c)
 		if err != nil {
 			c.Println(err)
@@ -329,13 +400,22 @@ func (c *Command) Help() error {
 	return nil
 }
 
-// UsageString return usage string.
+// UsageString returns usage string.
 func (c *Command) UsageString() string {
-	tmpOutput := c.output
+	// Storing normal writers
+	tmpOutput := c.outWriter
+	tmpErr := c.errWriter
+
 	bb := new(bytes.Buffer)
-	c.SetOutput(bb)
+	c.outWriter = bb
+	c.errWriter = bb
+
 	c.Usage()
-	c.output = tmpOutput
+
+	// Setting things back to normal
+	c.outWriter = tmpOutput
+	c.errWriter = tmpErr
+
 	return bb.String()
 }
 
@@ -793,6 +873,13 @@ func (c *Command) preRun() {
 	}
 }
 
+// ExecuteContext is the same as Execute(), but sets the ctx on the command.
+// Retrieve ctx by calling cmd.Context() inside your *Run lifecycle functions.
+func (c *Command) ExecuteContext(ctx context.Context) error {
+	c.ctx = ctx
+	return c.Execute()
+}
+
 // Execute uses the args (os.Args[1:] by default)
 // and run through the command tree finding appropriate matches
 // for commands and then corresponding flags.
@@ -803,6 +890,10 @@ func (c *Command) Execute() error {
 
 // ExecuteC executes the command.
 func (c *Command) ExecuteC() (cmd *Command, err error) {
+	if c.ctx == nil {
+		c.ctx = context.Background()
+	}
+
 	// Regardless of what command execute is called on, run on Root only
 	if c.HasParent() {
 		return c.Root().ExecuteC()
@@ -817,15 +908,16 @@ func (c *Command) ExecuteC() (cmd *Command, err error) {
 	// overriding
 	c.InitDefaultHelpCmd()
 
-	var args []string
+	args := c.args
 
 	// Workaround FAIL with "go test -v" or "cobra.test -test.v", see #155
 	if c.args == nil && filepath.Base(os.Args[0]) != "cobra.test" {
 		args = os.Args[1:]
-	} else {
-		args = c.args
 	}
 
+	// initialize the hidden command to be used for bash completion
+	c.initCompleteCmd(args)
+
 	var flags []string
 	if c.TraverseChildren {
 		cmd, flags, err = c.Traverse(args)
@@ -849,6 +941,12 @@ func (c *Command) ExecuteC() (cmd *Command, err error) {
 		cmd.commandCalledAs.name = cmd.Name()
 	}
 
+	// We have to pass global context to children command
+	// if context is present on the parent command.
+	if cmd.ctx == nil {
+		cmd.ctx = c.ctx
+	}
+
 	err = cmd.execute(flags)
 	if err != nil {
 		// Always show help if requested, even if SilenceErrors is in
@@ -932,7 +1030,11 @@ func (c *Command) InitDefaultVersionFlag() {
 		} else {
 			usage += c.Name()
 		}
-		c.Flags().Bool("version", false, usage)
+		if c.Flags().ShorthandLookup("v") == nil {
+			c.Flags().BoolP("version", "v", false, usage)
+		} else {
+			c.Flags().Bool("version", false, usage)
+		}
 	}
 }
 
@@ -1070,6 +1172,21 @@ func (c *Command) Printf(format string, i ...interface{}) {
 	c.Print(fmt.Sprintf(format, i...))
 }
 
+// PrintErr is a convenience method to Print to the defined Err output, fallback to Stderr if not set.
+func (c *Command) PrintErr(i ...interface{}) {
+	fmt.Fprint(c.ErrOrStderr(), i...)
+}
+
+// PrintErrln is a convenience method to Println to the defined Err output, fallback to Stderr if not set.
+func (c *Command) PrintErrln(i ...interface{}) {
+	c.Print(fmt.Sprintln(i...))
+}
+
+// PrintErrf is a convenience method to Printf to the defined Err output, fallback to Stderr if not set.
+func (c *Command) PrintErrf(format string, i ...interface{}) {
+	c.Print(fmt.Sprintf(format, i...))
+}
+
 // CommandPath returns the full path to this command.
 func (c *Command) CommandPath() string {
 	if c.HasParent() {
@@ -1335,7 +1452,7 @@ func (c *Command) LocalFlags() *flag.FlagSet {
 	return c.lflags
 }
 
-// InheritedFlags returns all flags which were inherited from parents commands.
+// InheritedFlags returns all flags which were inherited from parent commands.
 func (c *Command) InheritedFlags() *flag.FlagSet {
 	c.mergePersistentFlags()
 
@@ -1470,7 +1587,7 @@ func (c *Command) ParseFlags(args []string) error {
 	beforeErrorBufLen := c.flagErrorBuf.Len()
 	c.mergePersistentFlags()
 
-	//do it here after merging all flags and just before parse
+	// do it here after merging all flags and just before parse
 	c.Flags().ParseErrorsWhitelist = flag.ParseErrorsWhitelist(c.FParseErrWhitelist)
 
 	err := c.Flags().Parse(args)
diff --git a/vendor/github.com/spf13/cobra/command_win.go b/vendor/github.com/spf13/cobra/command_win.go
index edec728e4f..8768b1736d 100644
--- a/vendor/github.com/spf13/cobra/command_win.go
+++ b/vendor/github.com/spf13/cobra/command_win.go
@@ -3,6 +3,7 @@
 package cobra
 
 import (
+	"fmt"
 	"os"
 	"time"
 
@@ -14,7 +15,12 @@ var preExecHookFn = preExecHook
 func preExecHook(c *Command) {
 	if MousetrapHelpText != "" && mousetrap.StartedByExplorer() {
 		c.Print(MousetrapHelpText)
-		time.Sleep(5 * time.Second)
+		if MousetrapDisplayDuration > 0 {
+			time.Sleep(MousetrapDisplayDuration)
+		} else {
+			c.Println("Press return to continue...")
+			fmt.Scanln()
+		}
 		os.Exit(1)
 	}
 }
diff --git a/vendor/github.com/spf13/cobra/custom_completions.go b/vendor/github.com/spf13/cobra/custom_completions.go
new file mode 100644
index 0000000000..ba57327c15
--- /dev/null
+++ b/vendor/github.com/spf13/cobra/custom_completions.go
@@ -0,0 +1,384 @@
+package cobra
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/spf13/pflag"
+)
+
+const (
+	// ShellCompRequestCmd is the name of the hidden command that is used to request
+	// completion results from the program.  It is used by the shell completion scripts.
+	ShellCompRequestCmd = "__complete"
+	// ShellCompNoDescRequestCmd is the name of the hidden command that is used to request
+	// completion results without their description.  It is used by the shell completion scripts.
+	ShellCompNoDescRequestCmd = "__completeNoDesc"
+)
+
+// Global map of flag completion functions.
+var flagCompletionFunctions = map[*pflag.Flag]func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective){}
+
+// ShellCompDirective is a bit map representing the different behaviors the shell
+// can be instructed to have once completions have been provided.
+type ShellCompDirective int
+
+const (
+	// ShellCompDirectiveError indicates an error occurred and completions should be ignored.
+	ShellCompDirectiveError ShellCompDirective = 1 << iota
+
+	// ShellCompDirectiveNoSpace indicates that the shell should not add a space
+	// after the completion even if there is a single completion provided.
+	ShellCompDirectiveNoSpace
+
+	// ShellCompDirectiveNoFileComp indicates that the shell should not provide
+	// file completion even when no completion is provided.
+	// This currently does not work for zsh or bash < 4
+	ShellCompDirectiveNoFileComp
+
+	// ShellCompDirectiveDefault indicates to let the shell perform its default
+	// behavior after completions have been provided.
+	ShellCompDirectiveDefault ShellCompDirective = 0
+)
+
+// RegisterFlagCompletionFunc should be called to register a function to provide completion for a flag.
+func (c *Command) RegisterFlagCompletionFunc(flagName string, f func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective)) error {
+	flag := c.Flag(flagName)
+	if flag == nil {
+		return fmt.Errorf("RegisterFlagCompletionFunc: flag '%s' does not exist", flagName)
+	}
+	if _, exists := flagCompletionFunctions[flag]; exists {
+		return fmt.Errorf("RegisterFlagCompletionFunc: flag '%s' already registered", flagName)
+	}
+	flagCompletionFunctions[flag] = f
+	return nil
+}
+
+// Returns a string listing the different directive enabled in the specified parameter
+func (d ShellCompDirective) string() string {
+	var directives []string
+	if d&ShellCompDirectiveError != 0 {
+		directives = append(directives, "ShellCompDirectiveError")
+	}
+	if d&ShellCompDirectiveNoSpace != 0 {
+		directives = append(directives, "ShellCompDirectiveNoSpace")
+	}
+	if d&ShellCompDirectiveNoFileComp != 0 {
+		directives = append(directives, "ShellCompDirectiveNoFileComp")
+	}
+	if len(directives) == 0 {
+		directives = append(directives, "ShellCompDirectiveDefault")
+	}
+
+	if d > ShellCompDirectiveError+ShellCompDirectiveNoSpace+ShellCompDirectiveNoFileComp {
+		return fmt.Sprintf("ERROR: unexpected ShellCompDirective value: %d", d)
+	}
+	return strings.Join(directives, ", ")
+}
+
+// Adds a special hidden command that can be used to request custom completions.
+func (c *Command) initCompleteCmd(args []string) {
+	completeCmd := &Command{
+		Use:                   fmt.Sprintf("%s [command-line]", ShellCompRequestCmd),
+		Aliases:               []string{ShellCompNoDescRequestCmd},
+		DisableFlagsInUseLine: true,
+		Hidden:                true,
+		DisableFlagParsing:    true,
+		Args:                  MinimumNArgs(1),
+		Short:                 "Request shell completion choices for the specified command-line",
+		Long: fmt.Sprintf("%[2]s is a special command that is used by the shell completion logic\n%[1]s",
+			"to request completion choices for the specified command-line.", ShellCompRequestCmd),
+		Run: func(cmd *Command, args []string) {
+			finalCmd, completions, directive, err := cmd.getCompletions(args)
+			if err != nil {
+				CompErrorln(err.Error())
+				// Keep going for multiple reasons:
+				// 1- There could be some valid completions even though there was an error
+				// 2- Even without completions, we need to print the directive
+			}
+
+			noDescriptions := (cmd.CalledAs() == ShellCompNoDescRequestCmd)
+			for _, comp := range completions {
+				if noDescriptions {
+					// Remove any description that may be included following a tab character.
+					comp = strings.Split(comp, "\t")[0]
+				}
+				// Print each possible completion to stdout for the completion script to consume.
+				fmt.Fprintln(finalCmd.OutOrStdout(), comp)
+			}
+
+			if directive > ShellCompDirectiveError+ShellCompDirectiveNoSpace+ShellCompDirectiveNoFileComp {
+				directive = ShellCompDirectiveDefault
+			}
+
+			// As the last printout, print the completion directive for the completion script to parse.
+			// The directive integer must be that last character following a single colon (:).
+			// The completion script expects :<directive>
+			fmt.Fprintf(finalCmd.OutOrStdout(), ":%d\n", directive)
+
+			// Print some helpful info to stderr for the user to understand.
+			// Output from stderr must be ignored by the completion script.
+			fmt.Fprintf(finalCmd.ErrOrStderr(), "Completion ended with directive: %s\n", directive.string())
+		},
+	}
+	c.AddCommand(completeCmd)
+	subCmd, _, err := c.Find(args)
+	if err != nil || subCmd.Name() != ShellCompRequestCmd {
+		// Only create this special command if it is actually being called.
+		// This reduces possible side-effects of creating such a command;
+		// for example, having this command would cause problems to a
+		// cobra program that only consists of the root command, since this
+		// command would cause the root command to suddenly have a subcommand.
+		c.RemoveCommand(completeCmd)
+	}
+}
+
+func (c *Command) getCompletions(args []string) (*Command, []string, ShellCompDirective, error) {
+	var completions []string
+
+	// The last argument, which is not completely typed by the user,
+	// should not be part of the list of arguments
+	toComplete := args[len(args)-1]
+	trimmedArgs := args[:len(args)-1]
+
+	// Find the real command for which completion must be performed
+	finalCmd, finalArgs, err := c.Root().Find(trimmedArgs)
+	if err != nil {
+		// Unable to find the real command. E.g., <program> someInvalidCmd <TAB>
+		return c, completions, ShellCompDirectiveDefault, fmt.Errorf("Unable to find a command for arguments: %v", trimmedArgs)
+	}
+
+	// When doing completion of a flag name, as soon as an argument starts with
+	// a '-' we know it is a flag.  We cannot use isFlagArg() here as it requires
+	// the flag to be complete
+	if len(toComplete) > 0 && toComplete[0] == '-' && !strings.Contains(toComplete, "=") {
+		// We are completing a flag name
+		finalCmd.NonInheritedFlags().VisitAll(func(flag *pflag.Flag) {
+			completions = append(completions, getFlagNameCompletions(flag, toComplete)...)
+		})
+		finalCmd.InheritedFlags().VisitAll(func(flag *pflag.Flag) {
+			completions = append(completions, getFlagNameCompletions(flag, toComplete)...)
+		})
+
+		directive := ShellCompDirectiveDefault
+		if len(completions) > 0 {
+			if strings.HasSuffix(completions[0], "=") {
+				directive = ShellCompDirectiveNoSpace
+			}
+		}
+		return finalCmd, completions, directive, nil
+	}
+
+	var flag *pflag.Flag
+	if !finalCmd.DisableFlagParsing {
+		// We only do flag completion if we are allowed to parse flags
+		// This is important for commands which have requested to do their own flag completion.
+		flag, finalArgs, toComplete, err = checkIfFlagCompletion(finalCmd, finalArgs, toComplete)
+		if err != nil {
+			// Error while attempting to parse flags
+			return finalCmd, completions, ShellCompDirectiveDefault, err
+		}
+	}
+
+	if flag == nil {
+		// Complete subcommand names
+		for _, subCmd := range finalCmd.Commands() {
+			if subCmd.IsAvailableCommand() && strings.HasPrefix(subCmd.Name(), toComplete) {
+				completions = append(completions, fmt.Sprintf("%s\t%s", subCmd.Name(), subCmd.Short))
+			}
+		}
+
+		if len(finalCmd.ValidArgs) > 0 {
+			// Always complete ValidArgs, even if we are completing a subcommand name.
+			// This is for commands that have both subcommands and ValidArgs.
+			for _, validArg := range finalCmd.ValidArgs {
+				if strings.HasPrefix(validArg, toComplete) {
+					completions = append(completions, validArg)
+				}
+			}
+
+			// If there are ValidArgs specified (even if they don't match), we stop completion.
+			// Only one of ValidArgs or ValidArgsFunction can be used for a single command.
+			return finalCmd, completions, ShellCompDirectiveNoFileComp, nil
+		}
+
+		// Always let the logic continue so as to add any ValidArgsFunction completions,
+		// even if we already found sub-commands.
+		// This is for commands that have subcommands but also specify a ValidArgsFunction.
+	}
+
+	// Parse the flags and extract the arguments to prepare for calling the completion function
+	if err = finalCmd.ParseFlags(finalArgs); err != nil {
+		return finalCmd, completions, ShellCompDirectiveDefault, fmt.Errorf("Error while parsing flags from args %v: %s", finalArgs, err.Error())
+	}
+
+	// We only remove the flags from the arguments if DisableFlagParsing is not set.
+	// This is important for commands which have requested to do their own flag completion.
+	if !finalCmd.DisableFlagParsing {
+		finalArgs = finalCmd.Flags().Args()
+	}
+
+	// Find the completion function for the flag or command
+	var completionFn func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective)
+	if flag != nil {
+		completionFn = flagCompletionFunctions[flag]
+	} else {
+		completionFn = finalCmd.ValidArgsFunction
+	}
+	if completionFn == nil {
+		// Go custom completion not supported/needed for this flag or command
+		return finalCmd, completions, ShellCompDirectiveDefault, nil
+	}
+
+	// Call the registered completion function to get the completions
+	comps, directive := completionFn(finalCmd, finalArgs, toComplete)
+	completions = append(completions, comps...)
+	return finalCmd, completions, directive, nil
+}
+
+func getFlagNameCompletions(flag *pflag.Flag, toComplete string) []string {
+	if nonCompletableFlag(flag) {
+		return []string{}
+	}
+
+	var completions []string
+	flagName := "--" + flag.Name
+	if strings.HasPrefix(flagName, toComplete) {
+		// Flag without the =
+		completions = append(completions, fmt.Sprintf("%s\t%s", flagName, flag.Usage))
+
+		if len(flag.NoOptDefVal) == 0 {
+			// Flag requires a value, so it can be suffixed with =
+			flagName += "="
+			completions = append(completions, fmt.Sprintf("%s\t%s", flagName, flag.Usage))
+		}
+	}
+
+	flagName = "-" + flag.Shorthand
+	if len(flag.Shorthand) > 0 && strings.HasPrefix(flagName, toComplete) {
+		completions = append(completions, fmt.Sprintf("%s\t%s", flagName, flag.Usage))
+	}
+
+	return completions
+}
+
+func checkIfFlagCompletion(finalCmd *Command, args []string, lastArg string) (*pflag.Flag, []string, string, error) {
+	var flagName string
+	trimmedArgs := args
+	flagWithEqual := false
+	if isFlagArg(lastArg) {
+		if index := strings.Index(lastArg, "="); index >= 0 {
+			flagName = strings.TrimLeft(lastArg[:index], "-")
+			lastArg = lastArg[index+1:]
+			flagWithEqual = true
+		} else {
+			return nil, nil, "", errors.New("Unexpected completion request for flag")
+		}
+	}
+
+	if len(flagName) == 0 {
+		if len(args) > 0 {
+			prevArg := args[len(args)-1]
+			if isFlagArg(prevArg) {
+				// Only consider the case where the flag does not contain an =.
+				// If the flag contains an = it means it has already been fully processed,
+				// so we don't need to deal with it here.
+				if index := strings.Index(prevArg, "="); index < 0 {
+					flagName = strings.TrimLeft(prevArg, "-")
+
+					// Remove the uncompleted flag or else there could be an error created
+					// for an invalid value for that flag
+					trimmedArgs = args[:len(args)-1]
+				}
+			}
+		}
+	}
+
+	if len(flagName) == 0 {
+		// Not doing flag completion
+		return nil, trimmedArgs, lastArg, nil
+	}
+
+	flag := findFlag(finalCmd, flagName)
+	if flag == nil {
+		// Flag not supported by this command, nothing to complete
+		err := fmt.Errorf("Subcommand '%s' does not support flag '%s'", finalCmd.Name(), flagName)
+		return nil, nil, "", err
+	}
+
+	if !flagWithEqual {
+		if len(flag.NoOptDefVal) != 0 {
+			// We had assumed dealing with a two-word flag but the flag is a boolean flag.
+			// In that case, there is no value following it, so we are not really doing flag completion.
+			// Reset everything to do noun completion.
+			trimmedArgs = args
+			flag = nil
+		}
+	}
+
+	return flag, trimmedArgs, lastArg, nil
+}
+
+func findFlag(cmd *Command, name string) *pflag.Flag {
+	flagSet := cmd.Flags()
+	if len(name) == 1 {
+		// First convert the short flag into a long flag
+		// as the cmd.Flag() search only accepts long flags
+		if short := flagSet.ShorthandLookup(name); short != nil {
+			name = short.Name
+		} else {
+			set := cmd.InheritedFlags()
+			if short = set.ShorthandLookup(name); short != nil {
+				name = short.Name
+			} else {
+				return nil
+			}
+		}
+	}
+	return cmd.Flag(name)
+}
+
+// CompDebug prints the specified string to the same file as where the
+// completion script prints its logs.
+// Note that completion printouts should never be on stdout as they would
+// be wrongly interpreted as actual completion choices by the completion script.
+func CompDebug(msg string, printToStdErr bool) {
+	msg = fmt.Sprintf("[Debug] %s", msg)
+
+	// Such logs are only printed when the user has set the environment
+	// variable BASH_COMP_DEBUG_FILE to the path of some file to be used.
+	if path := os.Getenv("BASH_COMP_DEBUG_FILE"); path != "" {
+		f, err := os.OpenFile(path,
+			os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+		if err == nil {
+			defer f.Close()
+			f.WriteString(msg)
+		}
+	}
+
+	if printToStdErr {
+		// Must print to stderr for this not to be read by the completion script.
+		fmt.Fprintf(os.Stderr, msg)
+	}
+}
+
+// CompDebugln prints the specified string with a newline at the end
+// to the same file as where the completion script prints its logs.
+// Such logs are only printed when the user has set the environment
+// variable BASH_COMP_DEBUG_FILE to the path of some file to be used.
+func CompDebugln(msg string, printToStdErr bool) {
+	CompDebug(fmt.Sprintf("%s\n", msg), printToStdErr)
+}
+
+// CompError prints the specified completion message to stderr.
+func CompError(msg string) {
+	msg = fmt.Sprintf("[Error] %s", msg)
+	CompDebug(msg, true)
+}
+
+// CompErrorln prints the specified completion message to stderr with a newline at the end.
+func CompErrorln(msg string) {
+	CompError(fmt.Sprintf("%s\n", msg))
+}
diff --git a/vendor/github.com/spf13/cobra/doc/man_docs.go b/vendor/github.com/spf13/cobra/doc/man_docs.go
index baa48118a6..8c7fba44a8 100644
--- a/vendor/github.com/spf13/cobra/doc/man_docs.go
+++ b/vendor/github.com/spf13/cobra/doc/man_docs.go
@@ -20,10 +20,11 @@ import (
 	"os"
 	"path/filepath"
 	"sort"
+	"strconv"
 	"strings"
 	"time"
 
-	"github.com/cpuguy83/go-md2man/md2man"
+	"github.com/cpuguy83/go-md2man/v2/md2man"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 )
@@ -87,7 +88,7 @@ type GenManTreeOptions struct {
 
 // GenManHeader is a lot like the .TH header at the start of man pages. These
 // include the title, section, date, source, and manual. We will use the
-// current time if Date if unset and will use "Auto generated by spf13/cobra"
+// current time if Date is unset and will use "Auto generated by spf13/cobra"
 // if the Source is unset.
 type GenManHeader struct {
 	Title   string
@@ -104,14 +105,16 @@ func GenMan(cmd *cobra.Command, header *GenManHeader, w io.Writer) error {
 	if header == nil {
 		header = &GenManHeader{}
 	}
-	fillHeader(header, cmd.CommandPath())
+	if err := fillHeader(header, cmd.CommandPath()); err != nil {
+		return err
+	}
 
 	b := genMan(cmd, header)
 	_, err := w.Write(md2man.Render(b))
 	return err
 }
 
-func fillHeader(header *GenManHeader, name string) {
+func fillHeader(header *GenManHeader, name string) error {
 	if header.Title == "" {
 		header.Title = strings.ToUpper(strings.Replace(name, " ", "\\-", -1))
 	}
@@ -120,12 +123,20 @@ func fillHeader(header *GenManHeader, name string) {
 	}
 	if header.Date == nil {
 		now := time.Now()
+		if epoch := os.Getenv("SOURCE_DATE_EPOCH"); epoch != "" {
+			unixEpoch, err := strconv.ParseInt(epoch, 10, 64)
+			if err != nil {
+				return fmt.Errorf("invalid SOURCE_DATE_EPOCH: %v", err)
+			}
+			now = time.Unix(unixEpoch, 0)
+		}
 		header.Date = &now
 	}
 	header.date = (*header.Date).Format("Jan 2006")
 	if header.Source == "" {
 		header.Source = "Auto generated by spf13/cobra"
 	}
+	return nil
 }
 
 func manPreamble(buf *bytes.Buffer, header *GenManHeader, cmd *cobra.Command, dashedName string) {
diff --git a/vendor/github.com/spf13/cobra/fish_completions.go b/vendor/github.com/spf13/cobra/fish_completions.go
new file mode 100644
index 0000000000..c83609c83b
--- /dev/null
+++ b/vendor/github.com/spf13/cobra/fish_completions.go
@@ -0,0 +1,172 @@
+package cobra
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+)
+
+func genFishComp(buf *bytes.Buffer, name string, includeDesc bool) {
+	compCmd := ShellCompRequestCmd
+	if !includeDesc {
+		compCmd = ShellCompNoDescRequestCmd
+	}
+	buf.WriteString(fmt.Sprintf("# fish completion for %-36s -*- shell-script -*-\n", name))
+	buf.WriteString(fmt.Sprintf(`
+function __%[1]s_debug
+    set file "$BASH_COMP_DEBUG_FILE"
+    if test -n "$file"
+        echo "$argv" >> $file
+    end
+end
+
+function __%[1]s_perform_completion
+    __%[1]s_debug "Starting __%[1]s_perform_completion with: $argv"
+
+    set args (string split -- " " "$argv")
+    set lastArg "$args[-1]"
+
+    __%[1]s_debug "args: $args"
+    __%[1]s_debug "last arg: $lastArg"
+
+    set emptyArg ""
+    if test -z "$lastArg"
+        __%[1]s_debug "Setting emptyArg"
+        set emptyArg \"\"
+    end
+    __%[1]s_debug "emptyArg: $emptyArg"
+
+    set requestComp "$args[1] %[2]s $args[2..-1] $emptyArg"
+    __%[1]s_debug "Calling $requestComp"
+
+    set results (eval $requestComp 2> /dev/null)
+    set comps $results[1..-2]
+    set directiveLine $results[-1]
+
+    # For Fish, when completing a flag with an = (e.g., <program> -n=<TAB>)
+    # completions must be prefixed with the flag
+    set flagPrefix (string match -r -- '-.*=' "$lastArg")
+
+    __%[1]s_debug "Comps: $comps"
+    __%[1]s_debug "DirectiveLine: $directiveLine"
+    __%[1]s_debug "flagPrefix: $flagPrefix"
+
+    for comp in $comps
+        printf "%%s%%s\n" "$flagPrefix" "$comp"
+    end
+
+    printf "%%s\n" "$directiveLine"
+end
+
+# This function does three things:
+# 1- Obtain the completions and store them in the global __%[1]s_comp_results
+# 2- Set the __%[1]s_comp_do_file_comp flag if file completion should be performed
+#    and unset it otherwise
+# 3- Return true if the completion results are not empty
+function __%[1]s_prepare_completions
+    # Start fresh
+    set --erase __%[1]s_comp_do_file_comp
+    set --erase __%[1]s_comp_results
+
+    # Check if the command-line is already provided.  This is useful for testing.
+    if not set --query __%[1]s_comp_commandLine
+        set __%[1]s_comp_commandLine (commandline)
+    end
+    __%[1]s_debug "commandLine is: $__%[1]s_comp_commandLine"
+
+    set results (__%[1]s_perform_completion "$__%[1]s_comp_commandLine")
+    set --erase __%[1]s_comp_commandLine
+    __%[1]s_debug "Completion results: $results"
+
+    if test -z "$results"
+        __%[1]s_debug "No completion, probably due to a failure"
+        # Might as well do file completion, in case it helps
+        set --global __%[1]s_comp_do_file_comp 1
+        return 0
+    end
+
+    set directive (string sub --start 2 $results[-1])
+    set --global __%[1]s_comp_results $results[1..-2]
+
+    __%[1]s_debug "Completions are: $__%[1]s_comp_results"
+    __%[1]s_debug "Directive is: $directive"
+
+    if test -z "$directive"
+        set directive 0
+    end
+
+    set compErr (math (math --scale 0 $directive / %[3]d) %% 2)
+    if test $compErr -eq 1
+        __%[1]s_debug "Received error directive: aborting."
+        # Might as well do file completion, in case it helps
+        set --global __%[1]s_comp_do_file_comp 1
+        return 0
+    end
+
+    set nospace (math (math --scale 0 $directive / %[4]d) %% 2)
+    set nofiles (math (math --scale 0 $directive / %[5]d) %% 2)
+
+    __%[1]s_debug "nospace: $nospace, nofiles: $nofiles"
+
+    # Important not to quote the variable for count to work
+    set numComps (count $__%[1]s_comp_results)
+    __%[1]s_debug "numComps: $numComps"
+
+    if test $numComps -eq 1; and test $nospace -ne 0
+        # To support the "nospace" directive we trick the shell
+        # by outputting an extra, longer completion.
+        __%[1]s_debug "Adding second completion to perform nospace directive"
+        set --append __%[1]s_comp_results $__%[1]s_comp_results[1].
+    end
+
+    if test $numComps -eq 0; and test $nofiles -eq 0
+        __%[1]s_debug "Requesting file completion"
+        set --global __%[1]s_comp_do_file_comp 1
+    end
+
+    # If we don't want file completion, we must return true even if there
+    # are no completions found.  This is because fish will perform the last
+    # completion command, even if its condition is false, if no other
+    # completion command was triggered
+    return (not set --query __%[1]s_comp_do_file_comp)
+end
+
+# Remove any pre-existing completions for the program since we will be handling all of them
+# TODO this cleanup is not sufficient.  Fish completions are only loaded once the user triggers
+# them, so the below deletion will not work as it is run too early.  What else can we do?
+complete -c %[1]s -e
+
+# The order in which the below two lines are defined is very important so that __%[1]s_prepare_completions
+# is called first.  It is __%[1]s_prepare_completions that sets up the __%[1]s_comp_do_file_comp variable.
+#
+# This completion will be run second as complete commands are added FILO.
+# It triggers file completion choices when __%[1]s_comp_do_file_comp is set.
+complete -c %[1]s -n 'set --query __%[1]s_comp_do_file_comp'
+
+# This completion will be run first as complete commands are added FILO.
+# The call to __%[1]s_prepare_completions will setup both __%[1]s_comp_results abd __%[1]s_comp_do_file_comp.
+# It provides the program's completion choices.
+complete -c %[1]s -n '__%[1]s_prepare_completions' -f -a '$__%[1]s_comp_results'
+
+`, name, compCmd, ShellCompDirectiveError, ShellCompDirectiveNoSpace, ShellCompDirectiveNoFileComp))
+}
+
+// GenFishCompletion generates fish completion file and writes to the passed writer.
+func (c *Command) GenFishCompletion(w io.Writer, includeDesc bool) error {
+	buf := new(bytes.Buffer)
+	genFishComp(buf, c.Name(), includeDesc)
+	_, err := buf.WriteTo(w)
+	return err
+}
+
+// GenFishCompletionFile generates fish completion file.
+func (c *Command) GenFishCompletionFile(filename string, includeDesc bool) error {
+	outFile, err := os.Create(filename)
+	if err != nil {
+		return err
+	}
+	defer outFile.Close()
+
+	return c.GenFishCompletion(outFile, includeDesc)
+}
diff --git a/vendor/github.com/spf13/cobra/go.mod b/vendor/github.com/spf13/cobra/go.mod
new file mode 100644
index 0000000000..dea1030ba4
--- /dev/null
+++ b/vendor/github.com/spf13/cobra/go.mod
@@ -0,0 +1,12 @@
+module github.com/spf13/cobra
+
+go 1.12
+
+require (
+	github.com/cpuguy83/go-md2man/v2 v2.0.0
+	github.com/inconshreveable/mousetrap v1.0.0
+	github.com/mitchellh/go-homedir v1.1.0
+	github.com/spf13/pflag v1.0.3
+	github.com/spf13/viper v1.4.0
+	gopkg.in/yaml.v2 v2.2.2
+)
diff --git a/vendor/github.com/spf13/cobra/powershell_completions.go b/vendor/github.com/spf13/cobra/powershell_completions.go
new file mode 100644
index 0000000000..756c61b9dc
--- /dev/null
+++ b/vendor/github.com/spf13/cobra/powershell_completions.go
@@ -0,0 +1,100 @@
+// PowerShell completions are based on the amazing work from clap:
+// https://github.com/clap-rs/clap/blob/3294d18efe5f264d12c9035f404c7d189d4824e1/src/completions/powershell.rs
+//
+// The generated scripts require PowerShell v5.0+ (which comes Windows 10, but
+// can be downloaded separately for windows 7 or 8.1).
+
+package cobra
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	"github.com/spf13/pflag"
+)
+
+var powerShellCompletionTemplate = `using namespace System.Management.Automation
+using namespace System.Management.Automation.Language
+Register-ArgumentCompleter -Native -CommandName '%s' -ScriptBlock {
+    param($wordToComplete, $commandAst, $cursorPosition)
+    $commandElements = $commandAst.CommandElements
+    $command = @(
+        '%s'
+        for ($i = 1; $i -lt $commandElements.Count; $i++) {
+            $element = $commandElements[$i]
+            if ($element -isnot [StringConstantExpressionAst] -or
+                $element.StringConstantType -ne [StringConstantType]::BareWord -or
+                $element.Value.StartsWith('-')) {
+                break
+            }
+            $element.Value
+        }
+    ) -join ';'
+    $completions = @(switch ($command) {%s
+    })
+    $completions.Where{ $_.CompletionText -like "$wordToComplete*" } |
+        Sort-Object -Property ListItemText
+}`
+
+func generatePowerShellSubcommandCases(out io.Writer, cmd *Command, previousCommandName string) {
+	var cmdName string
+	if previousCommandName == "" {
+		cmdName = cmd.Name()
+	} else {
+		cmdName = fmt.Sprintf("%s;%s", previousCommandName, cmd.Name())
+	}
+
+	fmt.Fprintf(out, "\n        '%s' {", cmdName)
+
+	cmd.Flags().VisitAll(func(flag *pflag.Flag) {
+		if nonCompletableFlag(flag) {
+			return
+		}
+		usage := escapeStringForPowerShell(flag.Usage)
+		if len(flag.Shorthand) > 0 {
+			fmt.Fprintf(out, "\n            [CompletionResult]::new('-%s', '%s', [CompletionResultType]::ParameterName, '%s')", flag.Shorthand, flag.Shorthand, usage)
+		}
+		fmt.Fprintf(out, "\n            [CompletionResult]::new('--%s', '%s', [CompletionResultType]::ParameterName, '%s')", flag.Name, flag.Name, usage)
+	})
+
+	for _, subCmd := range cmd.Commands() {
+		usage := escapeStringForPowerShell(subCmd.Short)
+		fmt.Fprintf(out, "\n            [CompletionResult]::new('%s', '%s', [CompletionResultType]::ParameterValue, '%s')", subCmd.Name(), subCmd.Name(), usage)
+	}
+
+	fmt.Fprint(out, "\n            break\n        }")
+
+	for _, subCmd := range cmd.Commands() {
+		generatePowerShellSubcommandCases(out, subCmd, cmdName)
+	}
+}
+
+func escapeStringForPowerShell(s string) string {
+	return strings.Replace(s, "'", "''", -1)
+}
+
+// GenPowerShellCompletion generates PowerShell completion file and writes to the passed writer.
+func (c *Command) GenPowerShellCompletion(w io.Writer) error {
+	buf := new(bytes.Buffer)
+
+	var subCommandCases bytes.Buffer
+	generatePowerShellSubcommandCases(&subCommandCases, c, "")
+	fmt.Fprintf(buf, powerShellCompletionTemplate, c.Name(), c.Name(), subCommandCases.String())
+
+	_, err := buf.WriteTo(w)
+	return err
+}
+
+// GenPowerShellCompletionFile generates PowerShell completion file.
+func (c *Command) GenPowerShellCompletionFile(filename string) error {
+	outFile, err := os.Create(filename)
+	if err != nil {
+		return err
+	}
+	defer outFile.Close()
+
+	return c.GenPowerShellCompletion(outFile)
+}
diff --git a/vendor/github.com/spf13/cobra/shell_completions.go b/vendor/github.com/spf13/cobra/shell_completions.go
new file mode 100644
index 0000000000..ba0af9cb55
--- /dev/null
+++ b/vendor/github.com/spf13/cobra/shell_completions.go
@@ -0,0 +1,85 @@
+package cobra
+
+import (
+	"github.com/spf13/pflag"
+)
+
+// MarkFlagRequired adds the BashCompOneRequiredFlag annotation to the named flag if it exists,
+// and causes your command to report an error if invoked without the flag.
+func (c *Command) MarkFlagRequired(name string) error {
+	return MarkFlagRequired(c.Flags(), name)
+}
+
+// MarkPersistentFlagRequired adds the BashCompOneRequiredFlag annotation to the named persistent flag if it exists,
+// and causes your command to report an error if invoked without the flag.
+func (c *Command) MarkPersistentFlagRequired(name string) error {
+	return MarkFlagRequired(c.PersistentFlags(), name)
+}
+
+// MarkFlagRequired adds the BashCompOneRequiredFlag annotation to the named flag if it exists,
+// and causes your command to report an error if invoked without the flag.
+func MarkFlagRequired(flags *pflag.FlagSet, name string) error {
+	return flags.SetAnnotation(name, BashCompOneRequiredFlag, []string{"true"})
+}
+
+// MarkFlagFilename adds the BashCompFilenameExt annotation to the named flag, if it exists.
+// Generated bash autocompletion will select filenames for the flag, limiting to named extensions if provided.
+func (c *Command) MarkFlagFilename(name string, extensions ...string) error {
+	return MarkFlagFilename(c.Flags(), name, extensions...)
+}
+
+// MarkFlagCustom adds the BashCompCustom annotation to the named flag, if it exists.
+// Generated bash autocompletion will call the bash function f for the flag.
+func (c *Command) MarkFlagCustom(name string, f string) error {
+	return MarkFlagCustom(c.Flags(), name, f)
+}
+
+// MarkPersistentFlagFilename instructs the various shell completion
+// implementations to limit completions for this persistent flag to the
+// specified extensions (patterns).
+//
+// Shell Completion compatibility matrix: bash, zsh
+func (c *Command) MarkPersistentFlagFilename(name string, extensions ...string) error {
+	return MarkFlagFilename(c.PersistentFlags(), name, extensions...)
+}
+
+// MarkFlagFilename instructs the various shell completion implementations to
+// limit completions for this flag to the specified extensions (patterns).
+//
+// Shell Completion compatibility matrix: bash, zsh
+func MarkFlagFilename(flags *pflag.FlagSet, name string, extensions ...string) error {
+	return flags.SetAnnotation(name, BashCompFilenameExt, extensions)
+}
+
+// MarkFlagCustom instructs the various shell completion implementations to
+// limit completions for this flag to the specified extensions (patterns).
+//
+// Shell Completion compatibility matrix: bash, zsh
+func MarkFlagCustom(flags *pflag.FlagSet, name string, f string) error {
+	return flags.SetAnnotation(name, BashCompCustom, []string{f})
+}
+
+// MarkFlagDirname instructs the various shell completion implementations to
+// complete only directories with this named flag.
+//
+// Shell Completion compatibility matrix: zsh
+func (c *Command) MarkFlagDirname(name string) error {
+	return MarkFlagDirname(c.Flags(), name)
+}
+
+// MarkPersistentFlagDirname instructs the various shell completion
+// implementations to complete only directories with this persistent named flag.
+//
+// Shell Completion compatibility matrix: zsh
+func (c *Command) MarkPersistentFlagDirname(name string) error {
+	return MarkFlagDirname(c.PersistentFlags(), name)
+}
+
+// MarkFlagDirname instructs the various shell completion implementations to
+// complete only directories with this specified flag.
+//
+// Shell Completion compatibility matrix: zsh
+func MarkFlagDirname(flags *pflag.FlagSet, name string) error {
+	zshPattern := "-(/)"
+	return flags.SetAnnotation(name, zshCompDirname, []string{zshPattern})
+}
diff --git a/vendor/github.com/spf13/cobra/zsh_completions.go b/vendor/github.com/spf13/cobra/zsh_completions.go
index 889c22e273..12755482f0 100644
--- a/vendor/github.com/spf13/cobra/zsh_completions.go
+++ b/vendor/github.com/spf13/cobra/zsh_completions.go
@@ -1,13 +1,102 @@
 package cobra
 
 import (
-	"bytes"
+	"encoding/json"
 	"fmt"
 	"io"
 	"os"
+	"sort"
 	"strings"
+	"text/template"
+
+	"github.com/spf13/pflag"
 )
 
+const (
+	zshCompArgumentAnnotation   = "cobra_annotations_zsh_completion_argument_annotation"
+	zshCompArgumentFilenameComp = "cobra_annotations_zsh_completion_argument_file_completion"
+	zshCompArgumentWordComp     = "cobra_annotations_zsh_completion_argument_word_completion"
+	zshCompDirname              = "cobra_annotations_zsh_dirname"
+)
+
+var (
+	zshCompFuncMap = template.FuncMap{
+		"genZshFuncName":              zshCompGenFuncName,
+		"extractFlags":                zshCompExtractFlag,
+		"genFlagEntryForZshArguments": zshCompGenFlagEntryForArguments,
+		"extractArgsCompletions":      zshCompExtractArgumentCompletionHintsForRendering,
+	}
+	zshCompletionText = `
+{{/* should accept Command (that contains subcommands) as parameter */}}
+{{define "argumentsC" -}}
+{{ $cmdPath := genZshFuncName .}}
+function {{$cmdPath}} {
+  local -a commands
+
+  _arguments -C \{{- range extractFlags .}}
+    {{genFlagEntryForZshArguments .}} \{{- end}}
+    "1: :->cmnds" \
+    "*::arg:->args"
+
+  case $state in
+  cmnds)
+    commands=({{range .Commands}}{{if not .Hidden}}
+      "{{.Name}}:{{.Short}}"{{end}}{{end}}
+    )
+    _describe "command" commands
+    ;;
+  esac
+
+  case "$words[1]" in {{- range .Commands}}{{if not .Hidden}}
+  {{.Name}})
+    {{$cmdPath}}_{{.Name}}
+    ;;{{end}}{{end}}
+  esac
+}
+{{range .Commands}}{{if not .Hidden}}
+{{template "selectCmdTemplate" .}}
+{{- end}}{{end}}
+{{- end}}
+
+{{/* should accept Command without subcommands as parameter */}}
+{{define "arguments" -}}
+function {{genZshFuncName .}} {
+{{"  _arguments"}}{{range extractFlags .}} \
+    {{genFlagEntryForZshArguments . -}}
+{{end}}{{range extractArgsCompletions .}} \
+    {{.}}{{end}}
+}
+{{end}}
+
+{{/* dispatcher for commands with or without subcommands */}}
+{{define "selectCmdTemplate" -}}
+{{if .Hidden}}{{/* ignore hidden*/}}{{else -}}
+{{if .Commands}}{{template "argumentsC" .}}{{else}}{{template "arguments" .}}{{end}}
+{{- end}}
+{{- end}}
+
+{{/* template entry point */}}
+{{define "Main" -}}
+#compdef _{{.Name}} {{.Name}}
+
+{{template "selectCmdTemplate" .}}
+{{end}}
+`
+)
+
+// zshCompArgsAnnotation is used to encode/decode zsh completion for
+// arguments to/from Command.Annotations.
+type zshCompArgsAnnotation map[int]zshCompArgHint
+
+type zshCompArgHint struct {
+	// Indicates the type of the completion to use. One of:
+	// zshCompArgumentFilenameComp or zshCompArgumentWordComp
+	Tipe string `json:"type"`
+
+	// A value for the type above (globs for file completion or words)
+	Options []string `json:"options"`
+}
+
 // GenZshCompletionFile generates zsh completion file.
 func (c *Command) GenZshCompletionFile(filename string) error {
 	outFile, err := os.Create(filename)
@@ -19,108 +108,229 @@ func (c *Command) GenZshCompletionFile(filename string) error {
 	return c.GenZshCompletion(outFile)
 }
 
-// GenZshCompletion generates a zsh completion file and writes to the passed writer.
+// GenZshCompletion generates a zsh completion file and writes to the passed
+// writer. The completion always run on the root command regardless of the
+// command it was called from.
 func (c *Command) GenZshCompletion(w io.Writer) error {
-	buf := new(bytes.Buffer)
-
-	writeHeader(buf, c)
-	maxDepth := maxDepth(c)
-	writeLevelMapping(buf, maxDepth)
-	writeLevelCases(buf, maxDepth, c)
-
-	_, err := buf.WriteTo(w)
-	return err
-}
-
-func writeHeader(w io.Writer, cmd *Command) {
-	fmt.Fprintf(w, "#compdef %s\n\n", cmd.Name())
-}
-
-func maxDepth(c *Command) int {
-	if len(c.Commands()) == 0 {
-		return 0
+	tmpl, err := template.New("Main").Funcs(zshCompFuncMap).Parse(zshCompletionText)
+	if err != nil {
+		return fmt.Errorf("error creating zsh completion template: %v", err)
 	}
-	maxDepthSub := 0
-	for _, s := range c.Commands() {
-		subDepth := maxDepth(s)
-		if subDepth > maxDepthSub {
-			maxDepthSub = subDepth
+	return tmpl.Execute(w, c.Root())
+}
+
+// MarkZshCompPositionalArgumentFile marks the specified argument (first
+// argument is 1) as completed by file selection. patterns (e.g. "*.txt") are
+// optional - if not provided the completion will search for all files.
+func (c *Command) MarkZshCompPositionalArgumentFile(argPosition int, patterns ...string) error {
+	if argPosition < 1 {
+		return fmt.Errorf("Invalid argument position (%d)", argPosition)
+	}
+	annotation, err := c.zshCompGetArgsAnnotations()
+	if err != nil {
+		return err
+	}
+	if c.zshcompArgsAnnotationnIsDuplicatePosition(annotation, argPosition) {
+		return fmt.Errorf("Duplicate annotation for positional argument at index %d", argPosition)
+	}
+	annotation[argPosition] = zshCompArgHint{
+		Tipe:    zshCompArgumentFilenameComp,
+		Options: patterns,
+	}
+	return c.zshCompSetArgsAnnotations(annotation)
+}
+
+// MarkZshCompPositionalArgumentWords marks the specified positional argument
+// (first argument is 1) as completed by the provided words. At east one word
+// must be provided, spaces within words will be offered completion with
+// "word\ word".
+func (c *Command) MarkZshCompPositionalArgumentWords(argPosition int, words ...string) error {
+	if argPosition < 1 {
+		return fmt.Errorf("Invalid argument position (%d)", argPosition)
+	}
+	if len(words) == 0 {
+		return fmt.Errorf("Trying to set empty word list for positional argument %d", argPosition)
+	}
+	annotation, err := c.zshCompGetArgsAnnotations()
+	if err != nil {
+		return err
+	}
+	if c.zshcompArgsAnnotationnIsDuplicatePosition(annotation, argPosition) {
+		return fmt.Errorf("Duplicate annotation for positional argument at index %d", argPosition)
+	}
+	annotation[argPosition] = zshCompArgHint{
+		Tipe:    zshCompArgumentWordComp,
+		Options: words,
+	}
+	return c.zshCompSetArgsAnnotations(annotation)
+}
+
+func zshCompExtractArgumentCompletionHintsForRendering(c *Command) ([]string, error) {
+	var result []string
+	annotation, err := c.zshCompGetArgsAnnotations()
+	if err != nil {
+		return nil, err
+	}
+	for k, v := range annotation {
+		s, err := zshCompRenderZshCompArgHint(k, v)
+		if err != nil {
+			return nil, err
+		}
+		result = append(result, s)
+	}
+	if len(c.ValidArgs) > 0 {
+		if _, positionOneExists := annotation[1]; !positionOneExists {
+			s, err := zshCompRenderZshCompArgHint(1, zshCompArgHint{
+				Tipe:    zshCompArgumentWordComp,
+				Options: c.ValidArgs,
+			})
+			if err != nil {
+				return nil, err
+			}
+			result = append(result, s)
 		}
 	}
-	return 1 + maxDepthSub
+	sort.Strings(result)
+	return result, nil
 }
 
-func writeLevelMapping(w io.Writer, numLevels int) {
-	fmt.Fprintln(w, `_arguments \`)
-	for i := 1; i <= numLevels; i++ {
-		fmt.Fprintf(w, `  '%d: :->level%d' \`, i, i)
-		fmt.Fprintln(w)
-	}
-	fmt.Fprintf(w, `  '%d: :%s'`, numLevels+1, "_files")
-	fmt.Fprintln(w)
-}
-
-func writeLevelCases(w io.Writer, maxDepth int, root *Command) {
-	fmt.Fprintln(w, "case $state in")
-	defer fmt.Fprintln(w, "esac")
-
-	for i := 1; i <= maxDepth; i++ {
-		fmt.Fprintf(w, "  level%d)\n", i)
-		writeLevel(w, root, i)
-		fmt.Fprintln(w, "  ;;")
-	}
-	fmt.Fprintln(w, "  *)")
-	fmt.Fprintln(w, "    _arguments '*: :_files'")
-	fmt.Fprintln(w, "  ;;")
-}
-
-func writeLevel(w io.Writer, root *Command, i int) {
-	fmt.Fprintf(w, "    case $words[%d] in\n", i)
-	defer fmt.Fprintln(w, "    esac")
-
-	commands := filterByLevel(root, i)
-	byParent := groupByParent(commands)
-
-	for p, c := range byParent {
-		names := names(c)
-		fmt.Fprintf(w, "      %s)\n", p)
-		fmt.Fprintf(w, "        _arguments '%d: :(%s)'\n", i, strings.Join(names, " "))
-		fmt.Fprintln(w, "      ;;")
-	}
-	fmt.Fprintln(w, "      *)")
-	fmt.Fprintln(w, "        _arguments '*: :_files'")
-	fmt.Fprintln(w, "      ;;")
-
-}
-
-func filterByLevel(c *Command, l int) []*Command {
-	cs := make([]*Command, 0)
-	if l == 0 {
-		cs = append(cs, c)
-		return cs
-	}
-	for _, s := range c.Commands() {
-		cs = append(cs, filterByLevel(s, l-1)...)
-	}
-	return cs
-}
-
-func groupByParent(commands []*Command) map[string][]*Command {
-	m := make(map[string][]*Command)
-	for _, c := range commands {
-		parent := c.Parent()
-		if parent == nil {
-			continue
+func zshCompRenderZshCompArgHint(i int, z zshCompArgHint) (string, error) {
+	switch t := z.Tipe; t {
+	case zshCompArgumentFilenameComp:
+		var globs []string
+		for _, g := range z.Options {
+			globs = append(globs, fmt.Sprintf(`-g "%s"`, g))
 		}
-		m[parent.Name()] = append(m[parent.Name()], c)
+		return fmt.Sprintf(`'%d: :_files %s'`, i, strings.Join(globs, " ")), nil
+	case zshCompArgumentWordComp:
+		var words []string
+		for _, w := range z.Options {
+			words = append(words, fmt.Sprintf("%q", w))
+		}
+		return fmt.Sprintf(`'%d: :(%s)'`, i, strings.Join(words, " ")), nil
+	default:
+		return "", fmt.Errorf("Invalid zsh argument completion annotation: %s", t)
 	}
-	return m
 }
 
-func names(commands []*Command) []string {
-	ns := make([]string, len(commands))
-	for i, c := range commands {
-		ns[i] = c.Name()
-	}
-	return ns
+func (c *Command) zshcompArgsAnnotationnIsDuplicatePosition(annotation zshCompArgsAnnotation, position int) bool {
+	_, dup := annotation[position]
+	return dup
+}
+
+func (c *Command) zshCompGetArgsAnnotations() (zshCompArgsAnnotation, error) {
+	annotation := make(zshCompArgsAnnotation)
+	annotationString, ok := c.Annotations[zshCompArgumentAnnotation]
+	if !ok {
+		return annotation, nil
+	}
+	err := json.Unmarshal([]byte(annotationString), &annotation)
+	if err != nil {
+		return annotation, fmt.Errorf("Error unmarshaling zsh argument annotation: %v", err)
+	}
+	return annotation, nil
+}
+
+func (c *Command) zshCompSetArgsAnnotations(annotation zshCompArgsAnnotation) error {
+	jsn, err := json.Marshal(annotation)
+	if err != nil {
+		return fmt.Errorf("Error marshaling zsh argument annotation: %v", err)
+	}
+	if c.Annotations == nil {
+		c.Annotations = make(map[string]string)
+	}
+	c.Annotations[zshCompArgumentAnnotation] = string(jsn)
+	return nil
+}
+
+func zshCompGenFuncName(c *Command) string {
+	if c.HasParent() {
+		return zshCompGenFuncName(c.Parent()) + "_" + c.Name()
+	}
+	return "_" + c.Name()
+}
+
+func zshCompExtractFlag(c *Command) []*pflag.Flag {
+	var flags []*pflag.Flag
+	c.LocalFlags().VisitAll(func(f *pflag.Flag) {
+		if !f.Hidden {
+			flags = append(flags, f)
+		}
+	})
+	c.InheritedFlags().VisitAll(func(f *pflag.Flag) {
+		if !f.Hidden {
+			flags = append(flags, f)
+		}
+	})
+	return flags
+}
+
+// zshCompGenFlagEntryForArguments returns an entry that matches _arguments
+// zsh-completion parameters. It's too complicated to generate in a template.
+func zshCompGenFlagEntryForArguments(f *pflag.Flag) string {
+	if f.Name == "" || f.Shorthand == "" {
+		return zshCompGenFlagEntryForSingleOptionFlag(f)
+	}
+	return zshCompGenFlagEntryForMultiOptionFlag(f)
+}
+
+func zshCompGenFlagEntryForSingleOptionFlag(f *pflag.Flag) string {
+	var option, multiMark, extras string
+
+	if zshCompFlagCouldBeSpecifiedMoreThenOnce(f) {
+		multiMark = "*"
+	}
+
+	option = "--" + f.Name
+	if option == "--" {
+		option = "-" + f.Shorthand
+	}
+	extras = zshCompGenFlagEntryExtras(f)
+
+	return fmt.Sprintf(`'%s%s[%s]%s'`, multiMark, option, zshCompQuoteFlagDescription(f.Usage), extras)
+}
+
+func zshCompGenFlagEntryForMultiOptionFlag(f *pflag.Flag) string {
+	var options, parenMultiMark, curlyMultiMark, extras string
+
+	if zshCompFlagCouldBeSpecifiedMoreThenOnce(f) {
+		parenMultiMark = "*"
+		curlyMultiMark = "\\*"
+	}
+
+	options = fmt.Sprintf(`'(%s-%s %s--%s)'{%s-%s,%s--%s}`,
+		parenMultiMark, f.Shorthand, parenMultiMark, f.Name, curlyMultiMark, f.Shorthand, curlyMultiMark, f.Name)
+	extras = zshCompGenFlagEntryExtras(f)
+
+	return fmt.Sprintf(`%s'[%s]%s'`, options, zshCompQuoteFlagDescription(f.Usage), extras)
+}
+
+func zshCompGenFlagEntryExtras(f *pflag.Flag) string {
+	if f.NoOptDefVal != "" {
+		return ""
+	}
+
+	extras := ":" // allow options for flag (even without assistance)
+	for key, values := range f.Annotations {
+		switch key {
+		case zshCompDirname:
+			extras = fmt.Sprintf(":filename:_files -g %q", values[0])
+		case BashCompFilenameExt:
+			extras = ":filename:_files"
+			for _, pattern := range values {
+				extras = extras + fmt.Sprintf(` -g "%s"`, pattern)
+			}
+		}
+	}
+
+	return extras
+}
+
+func zshCompFlagCouldBeSpecifiedMoreThenOnce(f *pflag.Flag) bool {
+	return strings.Contains(f.Value.Type(), "Slice") ||
+		strings.Contains(f.Value.Type(), "Array")
+}
+
+func zshCompQuoteFlagDescription(s string) string {
+	return strings.Replace(s, "'", `'\''`, -1)
 }