Cosmetic Cleanups Incidental to Next Gen Modulestore Implementaton

Dcadams/email on invite

Optionally email students on enroll/un-enroll actions
by instructor from enrollment tab in LMS.

Studio - revises transparent Sass color vars to use rgba() method

move marketing iframe breakout script to inside existing conditional

Add handful of events to the Segment.io whitelist

Greater dir naming flexibility.

New course creator group.

Fix LMS-500: Random class in random module was None

Moves user activation from just clicking on reset password to following the link in the password reset email

Specify a different xcontent mongo db for the acceptance tests

Don't mention edge in the subject line; use same message for edx and edg...

Cleanup before adding external grader

Fixed Jasmine tests in light of Logger changes, and wrote test to cover case where data passed is not a dictionary

Updated diff-cover to version 0.1.3 to fix a bug