Fix (save-html.js): Added code to remove toc-nav node.

If there is a toc-nav node when saving a snapshot, remove it.  It is not
part of the document. It was added by fixup.js.

Should address #644

js/ui/save-html.js

@@ -8,6 +8,7 @@ define(
         var msg, doc, conf;
         var cleanup = function (rootEl) {
             $(".removeOnSave", rootEl).remove();
+            $("#toc-nav", rootEl).remove() ;
             utils.removeReSpec(rootEl);
         };
         return {