don't show sign out button when not signed in

ast/render.ts

@@ -1092,6 +1092,7 @@ module TDev
         static css = "<style>\n" +
                      "@page { margin: 1in; }\n" +
                       ".md-tutorial { font-size: 1.0em; line-height: 1.4em; }\n"+
+                      "@media print { .md-tutorial a:link:after, .md-tutorial a:visited:after  { content:\" (\" attr(href) \") \"; } }\n"+                      
                       ".parse-error, .decl { margin-bottom: 1em; }\n" +
                       ".parse-error, .error { color: #d00; }\n" +
                       ".hint { color: #444; }\n" +

editor/hub.ts

@@ -555,7 +555,7 @@ module TDev.Browser {
             m.add(div("wall-dialog-body", lf("Running against cloud services v{0}.", relId)));
             var btns: HTMLElement;
             m.add(btns = div("wall-dialog-buttons",
-                HTML.mkButton(lf("sign out"),() => TheEditor.logoutDialog()),
+                Cloud.getUserId() ? HTML.mkButton(lf("sign out"),() => TheEditor.logoutDialog()) : undefined,
                 link(lf("terms of use"), "/terms-of-use"),
                 link(lf("privacy and cookies"), "/privacy")
                 ));

www/editor.css

@@ -4924,6 +4924,11 @@ height: 2.2em;
   margin-bottom: 1.5em;
 }
 
+@media print {
+  .md-tutorial a:link:after, .md-tutorial a:visited:after
+  { content:" (" attr(href) ") "; }
+}
+
 .md-video-link {
   text-align:center;
   cursor:pointer;