2498: Implemented backend for metadata project

Added fields to models.  Implemented getting/setting metadata.  Added
tests.  Added migrations.
Added another youtube URL for testing

This one is used by the integration repo
Test improvements

Clear the cache after every test.  This makes the integration tests pass

Moved code that patches functions to a different class from our nose
plugin.  The nose plugin can do a more than just patch functions, so
let's try to keep it clean.

Handle logging better by letting the nose LogCapture do it.
Make SubtitleStorage.getLanguages() return Language objects

Before it was returning the raw data from the server.

Added versions attribute to Language.

Updated underscore version.  Stopped calling noConflict() in the
subtitles controllers file.  That made it inaccessible everywhere
else.  Use non-minified version of underscore for the subtitle editor,
we'll minify it ourselves when we build the media bundle.
2498: Initial work to get metadata in the editor

Add metadata for the current working subs in the editor_data variable.

Refactored code to get subtitles.  Made it use
format=json&sub_format=dfxp.  This way we can get things like
title/description/metadata from the response.

Changed the metadat h3's so we uppercase them with CSS.  This will
make things better once we translate the metadata type, since we don't
know if the translation will be uppercase or not.
2498: fix metadata type labels
2498: Display/update metadata in editor

Added a fix to autotext-bind to make things run in an $apply call.
2498: updated integration commit
2498: Display metadata on the video/subtitle page
Merge branch 'i-2498' into production