use correct sampling, refs #4452

git-svn-id: svn://develop.studip.de/studip/trunk@31268 c5b85792-5220-0410-ad23-ed5b6b8ad999
add performance timing for my courses, refs #4452

git-svn-id: svn://develop.studip.de/studip/trunk@31269 c5b85792-5220-0410-ad23-ed5b6b8ad999
equalize number of minutes when counting online users, fixes #4546

git-svn-id: svn://develop.studip.de/studip/trunk@31270 c5b85792-5220-0410-ad23-ed5b6b8ad999
measure users online, refs #4452

git-svn-id: svn://develop.studip.de/studip/trunk@31271 c5b85792-5220-0410-ad23-ed5b6b8ad999