Removed some clones (thanks to Teamscale)
Removed some more clones (that I found without Teamscale :-)
Oops, no 'this' in functions that are passed as parameters
Removed groupsAPI method getGroup, now we directly use groupstore instead.
Tests for the validate function in misc.
Tests for /groups/checkemailprefix
Tests for /checkurl in activities and announcements.
Moved the argument trimming into the validate function, added tests.
Merge pull request #715 from NicoleRauch/master

Removed clones, unified validation, added tests.