Rewrite videojs-chromecast in CoffeeScript

As a first step, i will rewrite the wohle videojs-chromecast plugin with coffeescript.
The code is very unreadable currently. I will leave the JS files until the new code has been tested with a Chromecast.

Tasks for this Pull request:
* [ ] Rewrite all files in src/ in CoffeeScript
* [ ] Rewrite Gruntfile to work with CoffeeScript
* [ ] Test the re-written code
* [ ] Delete all JS Files
* [ ] Rewrite the Gruntfile in CoffeeScript