Adding Codeception bootstrap with simple example

Hello,

since any unit test suite will not work with the intensive use of $_SERVER and $SESSION in the core files, I propose to use CodeCeption for the functional test suite.

You only have to configure the url of your local development server in "acceptance.suite.yml" and then run the tests with "codecept.phar run"

I've added a simple test in HomepageCept.php

More info on http://codeception.com/quickstart

This will solve the issue #398 

Hope this helps :beers: