FE categorie change and selection implemented
[FEATURE] creating new Events in FE can use an old one as template
[FEATURE] event submission with categories
[BUGFIX] fix faulty ics configuration
[BUGFIX] make category selectable when editing the event
[WIP] Compatibility to TYPO3 CMS 6.1

Changed classnames and adapted to extbase changes
Recurrence not tested
TODO: Analyze why some EventIndexes have no event