Use django cache for OpenID provider store

changed vote button icon display mode to fight zoom bugs

added google analytics to all pages without a course object

Fix create-dev-env script for Mac OS 10.8 and latest stable rvm

Add support for video download link

Replaced the previous method of getting it from HTTP_POST to use
django's mechanism, which may or may not use HTTP_HOST. However if an
attacker changes the request header, there is not much he can do since
he cannot recreate the association nonce.

Now when you hit the TAB key in codemirror, it will insert 4 spaces.

Firefox bug fix

Add styling for code grader responses

Make collapsibles not collapse the entire page

- need to set text of the link, not the document
- there was something funny with the operator precedence in the ternary operator (was getting 'true', instead of a string)

Kimth/js refactor

fix a bug: can_load() should check for the 'load' permission.

- triggered by anon users when all courses have started (or start dates are off).

Feature/victor/status banner

Add a download link to the video player. The link is defined in the
content xml using the following structure:

<video youtube="youtubestring">
  <source src="video_link"/>
</video>

Don't ignore .py files in static files dirs

- still needs style
- will cache for 10 seconds

Feature/cdodge/cms permissions management