btracey: add main.go for Gophercon and say hello to Brad

Change-Id: I88a73f0e14b5fce868dd7e5f2bb8afcb2fbd76ef
Reviewed-on: https://go-review.googlesource.com/48904
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

btracey/main.go

@@ -0,0 +1,11 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("Hello, Brad!")
+}