UNSTABLE. tijdelijke commit met aanpassingen van niek en pieterb.
UNTESTED: made it possible to change group memberships through a POST request on the group
UNSTABLE. but at least testable
Merge remote branch 'origin/pieterb_conext' into niek_vanalles

Conflicts:
	src/beehub_group.php
	src/beehub_sponsor.php
	views/sponsor.php