refs #3239
* Add citing directly from every view
* GUI changes as demande by the GUI-squad
* Postings have no title any more (but threads still do!)
* remove old forum-files and clean out lib/forum.inc.php (some plugins require that file, so keep it for while)


git-svn-id: svn://develop.studip.de/studip/trunk@25554 c5b85792-5220-0410-ad23-ed5b6b8ad999