Fixes #133 Fixes #114 Use modern text-search API

This means we are now bound to mongo >= 2.6, but we can take
advantage of the first-class text search features now, and removed
some of the crufty API calls.
No longer use pre-2.6 text search parameter on mongo startup
Filter search results from text search
Fixes #104. Use new search API in resource/search endpoint
For text search, default to sort by text score

Also fix the failing tests
Use mongo 2.6 on travis
Fix travis...
Merge pull request #269 from girder/text-parent-search-intersection

Enable searching by both parent and text filters