Adding a continuous build and test using  a python selenium based runner.

Features include;
 * Auto-install of dependencies including needed python modules and needed selenium drivers.
 * Ability to run against different browsers.
 * Ability to use a Selenium grid, including support for Sauce Labs.
 * Run in a headless mode by starting up VNC/xvfb - including uploading screenshots of failed tests to post-image.
 * Ability to output subunit format, allowing integration with testrepository and similar tools.
 * Runs on travis-ci

Things which need work
 * Testing the code works on Windows and Mac OS X
 * Use a better screenshot system.