Update the discussion area broken span tags
FOR-578
updating diff-cover to 0.5.0
dummy theme templates for testing
tests for PR 3769

Two out of three fail without PR 3769 but all pass with PR 3769.
Merge pull request #3770 from mlkwaqas/waqas/for578-post-selection-broken-span

Update the discussion area broken span tags
Merge pull request #4201 from edx/jtauber/test-PR3769

Test PR 3769 (Improves the way LMS serves /favicon.ico)
Merge pull request #4219 from edx/clytwynec/diff-cover-update

updating diff-cover to 0.5.0
Increases wait_for_notification timeout to 60 seconds
Uses present in bokchoy test
Merge pull request #4223 from edx/benmcmorran/increase-notification-timeout

Increases wait_for_notification timeout to 60 seconds
Display names, help text, and "deprecated" for Advanced Settings.

STUD-302, STUD-303
Merge pull request #4073 from edx/christina/advanced-settings-hack

Display names, help text, and "deprecated" for Advanced Settings.
Enable Mixed Modulestore STUD-1540
Refactor get_parent_locations STUD-1663
Merge pull request #3915 from edx/studio/uses-mixed-modulestore

Enable mixed modulestore
Fix saving error of video editor in non-english translation

Currently the code in ```tabs-aggregator.coffee``` uses the display name of a tab as the key to index the current tab. When a non-english translation is applied, the javascript code will get localized names instead of the original english names, which causes the following ```getValue``` function fails as it cannot reference the correct tab.