Use randomized mongo collection names in Studio tests

Crowdsourced Hints - "0.2 release"

collection names

Silence doc test errors/warnings

   Contains hotfix/2013-18-21

Fix/vik/oe state

Video Player: replace the description in the studio editing module for "subtitles" with "timed transcript"

Adam/turn off password autocomplete

Add combined coverage to `rake coverage`

Change `rake pep8` to ignore migrations files

fix error logging for unenrolling if enrollment not found

Add a python prefix for `diff-quality` task

Fixed coffeescript event logging error.

Fixed crowdsourced hinter dependence on self.field.append() not working.

Fixed a css bug in the hinter.

the bottom of the hint div, no matter what.

Still requires a little polishing, I think.

Hint submission is hidden behind a link, if there are hints to vote on.

Fixed broken tests.

Fixed some pep8 errors.

Removed the answer display next to voting.  (This was deemed distracting.)

Got rid of answer signatures - these don't work with approximate answers at all.  Instead, implemented comparison-based hint matching.

Tests are broken, hint manager is probably broken.