add whitespace to sidebar's list items, refs #3768

git-svn-id: svn://develop.studip.de/studip/trunk@30632 c5b85792-5220-0410-ad23-ed5b6b8ad999
re #3768

display topic-folder and threads

git-svn-id: svn://develop.studip.de/studip/trunk@30633 c5b85792-5220-0410-ad23-ed5b6b8ad999