Fix some comment related bugs.

* Snuownd failed to corrrectly render some novel variations of nested
emphasis.
* Table of contents links are now correctly stripped of formatting tags.
Expanded the sanitizer whitelist

Seriously? Who still uses <font>?
Fixed user highlighter not working properly in the dashboard
The previous commit was incomplete
Fix for broken navigation in the autocomplete popup

jQuery's .index() method may have been used incorrectly. It now uses a
more reliable technique.
Merge pull request #418 from gamefreak/fixes

Various fixes