adjustment to sidebar help text on PDF textbook page in studio

Fixed upload test.  Also added information to testing.md

Auto auth can now accept parameters for user attributes.

Rename MITX_SETTING AUTOMATIC_AUTH_FOR_LOAD_TESTING -> AUTOMATIC_AUTH_FOR_TESTING because it will be used for acceptance testing also.

Add acceptance test for XML-only video content.

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.