Since we've had issues with the default video being incorrectly shown,
this creates an XML-only video and ensures that the correct
(non-default) Youtube ID is sent to the client.

Workaround for popup CSS path being wrong (tinymce).

Simplify save_grade and pass through answer_unknown

STUD-178

To increase portability of courses, have the Asset Index page display the classic /static/... URL shorthand.

fix crash in peer eval xmodule

Fix VideoAlpha acceptance test.

Update XBlock version

Changed css_selector

Send e-mail to STUDIO_REQUEST_EMAIL when user requests course creator privileges

Fix Firefox subsection datetime bug

Fix videoalpha import from xml

Add "Word Cloud" acceptance tests

VideoAlphaDescriptor inherits from EmptyDataRawDescriptor.
EmptyDataRawDescriptor is used for modules which might not have any
XML data, but require XmlDescriptor's functionality for
export/import. Without it, VideoAlphaModule would cause a crash on
export if any modules had an empty `self.data` field.

Don't use default video if HTML5 sources are given.

Clicking "Sync to <course>" should send an AJAX request with the datetimes
set to null, so that the server resets them.

Assign isExternal JS function to window object

Fix offline_gradecalc

When JS functions are defined with names, they are local variables, and inaccessible
if defined inside a closure. Django-Pipeline concatenates all of our JS into one
big closure. This function explicitly assings the function to a property of the
`window` object, so that it is accessible to other JS functions.