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
updated pdf viewer
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.
Add some optional policies around password resets, such as password reuse, forced password resets, allowed frequency of password resets
password history: just limit the result set range to simplify iteration logic
Added comment to getUserMedia call in photocapture.js
Doc: update xblock publish() function signature
Add in metric tracking to xqueue.

Covers external grading and certificates.
Changed wording for setting up ORA question.
ORA-351
Merge pull request #3100 from edx/waheed/ora351-change-wording-for-setting-up-ora-question

Changed wording for setting up ORA question.
Fix flaky acceptance test.
BLD-950: Update captions logic on front-end.
Fixed studio can't handle more than 9 lines in advanced settings.
STUD-1483
Merge pull request #3128 from edx/anton/transcript-generation

Update captions logic on front-end.
Merge pull request #3141 from edx/db/doc-xblock-signature

Doc: update xblock publish() function signature
Merge pull request #3138 from edx/db/add-getusermedia-note

Added comment to getUserMedia call in photocapture.js
Converted XModule to JavaScript. Added Jasmine tests.

Part of the process for removing CoffeeScript from
edx-platform dependencies. Covering XModule with JavaScript
Jasmine unit tests.
Merge pull request #3144 from edx/diana/monitor-xqueue-graders

Add in metric tracking to xqueue.
Remove unused function