- Tag matches allows a user to search for a single tag
-- Since testing for multiple tags would require converting the "tags"
string to an array which would most likely fail even for single tags
- Is new for quick searching of uploads or not uploads
* Add search form above table.
* Move thumbnail to left of table when viewing history of single post.
* Remove unrelated links from subnav menu.
* Fix bugs with changed_tags search.
* Add ability to search /post_versions by added tags, removed tags, or
changed tags (added or removed).
* Add 'History' link to the sidebar of the /posts index. This is a
shortcut for a /post_versions search of the current tag.
