RequireJS is out

Hi
so a couple of things I changed:

* Removed RequireJS
* Also removed the RequireJS example folder (didn't seem relevant anymore / too hard to change)
* Removed Grunt
* Introduced Gulp
* Introduced jshint for code quality
* Integrated Gulp with Karma + Bundle
* Updated README
* Split the README into other 2 files: CONTRIBUTING and ROADMAP

I'm not sure if there's a CI hooked to it yet but, if it does, then you will have to change the test run with the command line `gulp run-tests ci`

Not sure if we should commit the dist file of pact js but, if you feel like, we can change this easily.

Guess that's that :)
Actually, this should be the pact-mock_service gem, but I can update that.