BLD-1033: Fix transcript displaying on iPad.
Merge pull request #3824 from edx/anton/fix-transcript-on-ipad

Video: Fix transcript displaying on iPad.
BLD-1020: Video Player grading.
Add logger.
Add cum score save action test.
Add debug logging.
Address comments.
Add fix for the bok-choy test.
Address comments.
Add graded save state test.
Add docstring.
Address comments and fix bok-choy tests.