LMS-1310

LTI: Fix import/export.

fix video module issue with require.js

Move index code into index.js.

Added two states to HD control: HD off - HD on

Wait for non-blank link in course-overview test

and disable tests that fail for unrelated reasons

Added back on hover CC button functionality.

Fixing falling test. Added fix for RequireJS & XModule loader video race condition.
Removed unnecessary comments from SCSS and JS files.
Added entry to Change Log.

Add a11y to the calculator

Jkarni/fix/customtag error 

re-enable tender

Rename contentstore/views/requests to helpers

Make tests conform to new import UI

        Otherwise it's possible to reach stuck states.

This has caused confusion, since this file gets imported when trying to
import the requests library.  And besides, how was this file about
requests in the first place?  Helpers is a much better name.