Audio content type

Reuses the Video view

Refactored some of the names to 'Media', to make it more agnostic

NB, this is a basic start, more work to come styling up the control bar better

![screen shot 2014-07-28 at 12 14 32](https://cloud.githubusercontent.com/assets/74132/3719739/7559f51a-1648-11e4-8bb3-d935f5cdcf5e.png)

Video player relies on javascript, and we don't run javascript on any browsers where this is not supported though, right? (<=ie8 no css3 and no js)