Loading
--------------
http://stackoverflow.com/questions/8685038/tell-whether-video-is-loaded-or-not-in-javascript
http://stackoverflow.com/questions/5181865/checking-if-a-html5-video-is-ready

Events
--------------
https://developer.mozilla.org/en-US/docs/Web/API/HTMLMediaElement
https://developer.mozilla.org/en-US/docs/Web/Guide/Events/Media_events