Add feature to do auto signup with external auth
This adds a feature flag: AUTH_USE_MIT_CERTIFICATES_IMMEDIATE_SIGNUP
that does an automatic signup of users if they are using external authentcation.
Fixed PEP8 and indentation issues
Added tests for signup skipping
Corrected CMS tests so that one is passing, added external_auth to cms apps
Several pylint fixes and bad super call
Removing external_auth addition to cms, and skipping test
Refactor keypress activation for forum buttons

This removes the use of the space key to activate buttons, which is not
expected behavior.
Improve accessibility of inline discussions

The show/hide toggle now properly acts like a button, and focus is now
trapped on the loading element for both the show/hide action and loading
of a new page.
Change video transcripts to use locators instead of locations.

Part of STUD-870
BLD-525: Fix Numerical input to support mathematical operations.
Improve auth handling of Locators
Ensure user admin screen gets the union of all possibly matching group names.
Smarter default group naming.
STUD-1003
Merge pull request #1799 from edx/dhm/bug-1003

Improve auth handling of Locators
Update the XBlock version.
Merge pull request #1765 from edx/gprice/inline-discussion-a11y

Improve accessibility of inline discussions
Add comment.
Fix LTI max_score method.
Add min value.
Merge pull request #1182 from carsongee/add_mitx_ssl_bypass_signup

Add feature to do auto signup with external auth
Merge pull request #1810 from edx/anton/fix-math-operations-in-numerical-input

Fix Numerical input to support mathematical operations.
BLD-542: Add display name.
Make has_score to be XField insted of decriptor property.