[CLEANUP] #4320 Add more type hinting

Change-Id: Idbb8f55aee25cb0d8162b14b0c6e2071f45a613b
Reviewed-on: http://review.typo3.org/35607
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>