Add Request Animation Frame shim from Paul Irish
Switch to RequestAnimationFrame

instead of Janky setTimeout and setInterval switch over to
requestAnimationFrame and get 60fps on modern browsers.

- move all subtitle rendering into timer view.
- delete overly complex view using timeouts
- now pausing subtitle's actually pauses the subtitles.

Inspired by watching the famo.us guys talk about what they did to get
the best performance out of HTML:

http://youtu.be/f48_wJjmEw0