[TASK] Bump the version number to 0.5.76.

Also update the manual.

Change-Id: I8a8eba2ffdab984bff9df021d0ea634f8b9d0234
Reviewed-on: http://review.typo3.org/34711
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>