inject grammar into source.coffee

[koenpunt]

Turns this:

Into this:

Not sure if this is the recommended way of injecting it into 2 grammars. (there might be a more concise way of writing the selector?)

Also, the injected grammar includes source.js, which when injected into source.coffee, actually has to be source.coffee. Maybe there's a way of referring to the root grammar? (cc: @infininight)

[jjeising]

Injector would be fine for me, but we probably should find a fix for the includes before merging this.