Minor change to allow using `this` for jasmine suite

[togakangaroo]

Especially when writing coffeescript tests it is common to use this for variables in scope

A very minor change to allow this style

describe "a feature", ->
    async.beforeEach -> 
        @mockFoo = jasmine.createSpy()
        @sut = blah(mockFoo)

    it "calls foo", -> (expect @mockFoo).toHaveBeenCalled()