Support CoffeeScript code coverage 

Building on top of the work the @can3p has committed.  I found that the [CoffeeScript-redux][redux] compiler was too strict.  @jstamerj done an amazing job of switching [CoffeeScript-redux][redux] to standard [CoffeeScript][coffee-script] in [Ibrik][ibrik].

I just glued the bits together and updated the README to help avid CoffeeScript users add Coverage support to their projects.

This should resolve #12 and karma-runner/karma#622

Enjoy

[redux]:https://github.com/michaelficarra/CoffeeScriptRedux
[coffee-script]:https://github.com/jashkenas/coffee-script
[ibrik]:https://github.com/jstamerj/ibrik/tree/9d9db260e6f1e558d052996c198e742378311fc6