added travis continues integration config

Travis is a continues integration service that will run unittest every time someone commits or makes a pull request towards a git repo. The service is free for open source projects and i think its a good service and it will make sure that the code at github always passes the unittest. A example from my fork of pyglet-gui:https://travis-ci.org/Norberg/pyglet-gui

Follow the instructions on https://travis-ci.org on how to create a account to run it on your repo.