Cleanups for DataHandler (formerly known as TCEmain)
Be honest. Thinking about refactoring TCEmain (now \TYPO3\CMS\Core\DataHandling\DataHandler) scares the s*** out of you. But at some point we have to do it.
I think a basic cleanup will make further steps easier. So this change is about:
- Provide proper phpDoc comments for all properties and methods
- Fix some nobrainer code smells