saveMember now also gets the old member data.
GroupsAPI.updateSubscriptions() now accepts old and new email address and transfers subscriptions if the email addresses differ. Existing tests are adapted, new tests for email address change are added.
Merge remote-tracking branch 'upstream/master'
Merge pull request #91 from NicoleRauch/master

Beim Ändern der Mailadresse im Profil werden jetzt die Gruppen-Subskriptionen auch umgestellt
groups now only for submitted members / edit only for admins
merge and group editing safety