Group id is always transformed to lowercase because Sympa also transforms it to lowercase.
Tests must be adapted, not production code :-)
Explain downcasing in groupstore.
More test adaptions to lowercase and to required id field.
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'

Conflicts:
	test/groups/groupsAPI_test.js
Merge pull request #183 from NicoleRauch/master

Group ID ist jetzt immer lowercase (Sympa macht das auch so)