- added modifier to the function/method return error test as well
- some small cleanups
TSPHP-462 check that variable is initialised
- added new version of common component (includes isFullyInitialised etc.)
- implemented the new check, additional code in the reference tree walker was necessary as well as additional setScope calls in the definition walker
- added new integration tests for the new constraint
- had to fix quite a lot of existing tests since they were no longer valid due to the new constraint

TSPHP-463 check that method has a return value
- Simplified the check in the reference walker (no longer using an enum)
- Fixed the check in order that it returns the correct error message

- Added latest parser component
- Improved a few tests concerning readability and extensibility