Add a stand-alone logger if console is not there

[bishopZ]

like this: https://github.com/mrdoob/logger.js/blob/master/src/Logger.js

[bishopZ]

Good tutorial about unit testing

https://www.unboxedconsulting.com/blog/making-javascript-testing-in-the-browser-not-suck-with-sinon-js-part-1