Generate test coverage for the CoffeeScript code

[arximboldi]

Before we generated coverage for the JavaScript generated, which is not that useful. Now we generate coverage for the original Coffee sources.

First, we had to change our testing framework to Mocha + Chai + Sinon. This is so because coffee-istanbul does not work with jasmine-node.

Also, to avoid generating coverage for the generated code, we had to change the imports in the example scripts to include directly the Coffee sources. While this makes them slightly less portable and less useful as an example, this is probably alright.

[coveralls]

Coverage increased (+0.59%) to 93.93% when pulling 0061b055e433f3488f22d20a0f476054c865dafe on mocha-testing into a33371e18f7548027cf341b40b8c177b2c3e6717 on master.

[coveralls]

Coverage increased (+0.59%) to 93.93% when pulling c445abbcde66d2a867ba66e3e6a66bb7968c57cb on mocha-testing into a33371e18f7548027cf341b40b8c177b2c3e6717 on master.