get_courses doesn't return ErrorDescriptor
Add missing mimetypes for xblock resources
Add mimetype additions in studio startup
lms dashboard ignores errored courses
Temporarily disable capa name masking

There is a bug I need to fix when a student re-visits a problem that they
had solved previously without masking enabled, their old state does not
load correclty.

It's simplest to turn off masking now, and re-enable it with the whole fix.

The change here is a small deletion to remove the masking=True logic, and more
lengthy changes to adjust the tests.
Run bundle clean after bundle install

Running it beforehand was resulting in a corrupted state
if it was the first time bundle install was run.
removes qualaroo from studio (STUD-1684)
load js without specifying protocol
Merge pull request #3937 from edx/adam/remove-qualaroo-studio

removes qualaroo from studio (STUD-1684)
Merge pull request #3919 from edx/benpatterson/clean-up-rbenv

Ensure no old gems are left behind between test runs.
Add note strongly recommending .webm and .mp4 video format
Change Location, CourseLocator, etc to reference opaque-keys library
Merge pull request #3943 from edx/flowerhack/cleanup-opaque-keys

Change Location, CourseLocator, etc to reference opaque-keys library
BLD-724: ChoiceTextResponse i18n.
Fixed staff debug info endpoints for staff member.
LMS-2737
Merge pull request #3852 from edx/waheed/lms2737-fix-staff-debug-info-links

Fixed staff debug info endpoints for staff member.
Fixed links for units loaded via ajax.
LMS-2711
Merge pull request #3755 from edx/waheed/lms2711-staff-debug-links-fixed-for-all-units

Fixed links for units loaded via ajax.
Bok-Choy Video Tests Batch9
Merge pull request #3895 from edx/anton/i18n-choice-text-response

BLD-724: ChoiceTextResponse i18n.