Support Literate CoffeeScript

It would be nice to support literate coffeescript (http://coffeescript.org/#literate) for specs.

Its a good way to use unittests as form of documentation 

A spec can look for example like this:

Literate CoffeeScript
====================

This is a spec using written in Literate CoffeeScript

    describe 'Coffee.litcoffee', ->

        it 'should pass', ->
            expect(1+2).toEqual(3)