make embargo template theme-able

Use "Stanford-style" theming to enable you to put your own embargo
notice up.
missing themed embargo page fails safely to unthemed
Convert CAPA inputtype statuses from strings to objects, in order to
simplify css class management and internationalization of status strings
(potentially) displayed to the user.
Fixes LMS-1740 by activating the zooming diagram with the spacebar.
Add repsonse pagination to inline discussions
Add SHOW_PROGRESS_SUCCESS_BUTTON feature

Show a button at the top of lms/templates/courseware/progress.html if the
lowest nonzero grade cutoff has been reached. Introduce two settings:
PROGRESS_SUCCESS_BUTTON_URL is the href of that button (the course id is
appended); PROGRESS_SUCCESS_BUTTON_TEXT is the text, defaults to
"Download your certificate"
Make the SHOW_PROGRESS_SUCCESS_BUTTON feature more flexible

The button text default is now in the template and i18n-able, a
PROGRESS_SUCCESS_BUTTON_TEXT_OVERRIDE option is offered in settings.
The button url now uses string formatting.
The link to TECH_SUPPORT_EMAIL should have a mailto: protocol !
Temporarily disable CAPA problem "Check" button.

- update appropriate jasmine tests so that stubbed $postWithPrefix
respects a subset of jQuery promise API.
- add customization for checking state.
- display checking state while button is disabled.
- ensure checking state lasts for at least a second.
Add my name!
Updating ORA2 requirements for patch fix
Disable flaky acceptance tests.
Explicitly declare `tags` in dog stats increment calls
Fix source editor for the case of no CodeMirror editor.

In the HTML component, there is no longer a tabbed CodeMirror Editor. STUD-1516.
Update testing.md file.

Added information on output folder for auto screenshots.
Use the correct response when using login.
Merge pull request #3252 from edx/anton/disable-flaky-acceptance-tests

Video: Disable flaky acceptance tests.
Merge pull request #3253 from edx/sarina/fix-capa-calls

Explicitly declare `tags` in dog stats increment calls
Merge pull request #3244 from edx/christina/latex-bug-release

Fix source editor for the case of no CodeMirror editor.
Merge pull request #3256 from edx/diana/fix-grading-service-login

Return correct response when using _try_with_login