Merge pull request #183 from NicoleRauch/master

Group ID ist jetzt immer lowercase (Sympa macht das auch so)
Group-emails are also allowed to contain dashes.
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' of https://github.com/NicoleRauch/NeuePlattform-Implementierung

Conflicts:
	public/clientscripts/check-groupform.js