added basic phpunit support via travis-ci.org

phpunit testing via travis-ci.org

- just merge the request
- go to www.travis-ci.org and login with your github creds
- open https://travis-ci.org/profile (if you not get redirected there - you might be)
- activate the plugin
- DONE :smiling_imp:

This way we can catch errors with php versions we do not run ourselves