Fix course urls in enrollment emails (LMS-2217)
InstDash: check Auto-Enroll and Email Students boxes by default
Merge pull request #3300 from edx/sarina/lms-2217

Fix course urls in enrollment emails (LMS-2217)
HD control is hidden initially. On first play of video, when
player.getAvailableQualityLevels returns a non-empty array, it will eventually display, if HD qualities are available (highres, hd1080, hd720). [BLD-937]