Fixed the wiki model migrations.

- remove the duplicate addition of the Document.deleted field
- don't use a specific datetime for a few datetime fields (triggered by a bug in an old south)
- make sure the db_index parameter is set correctly
Merge pull request #1394 from jezdez/fix-wiki-migrations

Fixed the wiki model migrations.
Merge pull request #1393 from jezdez/wiki-models-cleanup

Minor cleanup of the wiki models module to appease my demons.
fix bug 917992 - add 'search in English' link
Merge pull request #1390 from groovecoder/search-results-link-to-english-917992

fix bug 917992 - add 'search in English' link
Add ability to the search view to be queried with AJAX.

It'll return a rendered list of search results, with the same query
parameters.