Initial CoffeeScript support

## Important!
First merge codecombat/aether#41 and create a tag for version `0.1.17` as this pull-request is depending on the new version.

## General
Levels can be now solved using CoffeeScript. However this is just an initial version. Features that are still missing:

- automatic change of existing code JS <=> CS
- correct displaying of errors in Ace. For more details check codecombat/aether#42