Add option to force videos to play in hd.

[mdsitton]

Once nice thing about hd videos generally you get higher sound quality going up to 720p above that there isn't any difference.

May be a place to start for forcing hd? http://stackoverflow.com/questions/7582336/force-youtube-embed-to-start-in-720p

Shows what audio formats are for past and presently encoded videos: http://www.h3xed.com/web-and-internet/youtube-audio-quality-bitrate-240p-360p-480p-720p-1080p

[martindale]

+1 on this. We're using a YouTube plugin for Video.js for this, so I'm not sure how to accomplish this -- what are your thoughts on this, @eXon?