Move sub and transform login into Sweeteners
Only allow one sweetener per type
Creamerscript is now just a compiling framework

All Parsing and Transforming logic has been moved into the
creamerscript-sweeteners project. This was done to make custom syntax
extensions possible.

Sweeteners inherit from Creamerscript::Sweeteners::Base and implement
the logic needed to parse out code and later turn it into Coffeescript.
Since the Compiler is just a framework for using Sweeteners, you can
pick and choose which syntax features you want.