- "Current" is now most like the old format
-- It is therefore now the default for post versions
- Only show the actual edits in their own column
- Show the current state at that version in another column
- On the "previous" view, don't double-show full list of tags for
the first post versions, so leave edits blank
* 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.