First pass at ARIA. Video player buttons announce themselves as button when used with a screen reader
All buttons have an ARIA role, name , and state
Volume slider announces its name and value to screen readers
Progress slider announces its nabe and value to screen readers
Disabled one test in video_quality_control
Code cleanup
Added more explanatory states to the Volume, Fullscreen, HD, and CC controls
Fixed failing test.
Addressed PR comments
Added changes made to video.html to fixtures. Addressed latest PR comments
Merge pull request #1175 from edx/jmclaus_bugfix_video_player_controls_a11y

Bug fix video player controls a11y