Travis

So I was playing with Travis and wondering if we could use our own stuff to run the tests.
Looks like this:
* [TEST](https://travis-ci.org/elkuku/jissues/jobs/18319497) **FAIL** with a checkstyle warning 
* [TEST](https://travis-ci.org/elkuku/jissues/jobs/18319638) **FAIL** with a PHPUnit error 
* [TEST](https://travis-ci.org/elkuku/jissues/jobs/18319589) **FAIL** with a checkstyle warning and  a PHPUnit error 
* [TEST](https://travis-ci.org/elkuku/jissues/jobs/18319216) **SUCCESS** 
* Errors in language files currently don't make the build fail (but they could)

Apart from adding the possibility to make the build fail on checkstyle errors (which wasn't possible before) it also reduces the build time from about four minutes to one and reduces the amount of dependencies to download trying to make the world a better place by saving valuable resources.
:wink: