Refactor tests and make most of them work on Travis

* Move functional tests to tests/Functional and unit tests to tests/Unit
* Inherit those tests from the appropriate base testcases from TYPO3 core
* Slightly clean tests up and adapt them to new testing framework requirements and possibilities
* Provide a .travis.yml that executes the tests properly
* Allow failure on TYPO3 master as this requires even more changes in tests and extension