Adds a testing framework

This PR adds some phpunit-files to make testing easier as well as adding some files to enable testing via TravisCI.

Tests can be placed inside the ```test```-folder and a simple ```phpunit``` will then execute them. You might have to execute ```composer dump-autoload``` to get the autoloading right.

The Repository can also be added to travis-CI.org and on every commit the tests are executed on all PHP-Versions including hhvm. The Code-Coverage only includes the coverage of the tested files. All not tested files are not included!