Add "Imported" state to Studio video upload page

Updated edx-oauth2-provider to 0.5.1

DOC: Enhance Content Group and Experiment Group Config Sidebar Help

Adding phil_mcgachey@harvard.edu to the AUTHORS list

Add proxy to allow IE9 to make xdomain requests

skip acid block tests [TE-812]

Imported VAL videos get the value "imported" for their status. We
considered not including imported videos on the upload page but have
instead decided to include them, so it is necessary to have a display
string for the imported status value.

log and ignore invlaid/deleted courses in Enrollment API

Adds an /xdomain_proxy.html endpoint that serves
the proxy file from the xdomain library.  This
allows IE9 users to iframe in the proxy page
to simulate a cross-domain request with cookies.

change education level option label to read "Associate" degree

Remove mocked has_dynamic_children method.

ECOM-1273

Include VAL data in video module export/import

This is required so that an a video module exported by one Open edX
deployment and imported by another will work correctly if it contains an
edx_video_id but does not populate other URL fields.

JIRA: MA-110

block conversion.

Make BulkAssertionTest.bulk_assertions work with any assert* method

Fix string extraction error in underscore files

Pass standard list of xblock mixins to MixedModulestore in tests

Entrance exam gating

The written style ```interpolate(gettext('some text'), {...}, ...)``` will will cause the string inside gettext() not be extracted.
So a separate line is needed for ```gettext``` when gettext function is directly called inside a call to the interpolate function.

added READMEs for top level directories

- added entrance exam check on course info
- staff can by pass gating and added tests
- refined gating logic
- changes after rebasing with Asad's branch
- check ENTRANCE_EXAMS feature is enabled
- updated test to reflect new logic
- catering anonymous user in entrance exam permission
- fixed broken tests
- change after feedback on 16/3
- fix for a broken test
- created new entrance_exams module
- fixed quality error and improved test coverage
- put get_required_content back in milestones helper
- Refactored entrance exams logic
- Refactored tabs logic
- Fixed broken unit test
- changes after feedback from dan-f on 3/27
- removed unnecessary user.is_anonymous check
- Addressed PR feedback
- Addressed commit-specific feedback
- Rework guard clauses
- Add coverage for course info case

Fixed i18n Problem with xBlock Menu

Convert Vertical XModule to pure Vertical XBlock.

mattdrayer/SOL-461: Student dashboard clean-up

Remove timer_expiration_duration (leftover from Pearson proctored exams)

Fix two missing replacements of {studio_name}