FIX Privilege escalation through Group hierarchy setting (SS-2013-003)

See http://www.silverstripe.org/ss-2013-003-privilege-escalation-through-group-hierarchy-setting/
FIX Privilege escalation through APPLY_ROLES assignment (SS-2013-005)

See http://www.silverstripe.org/ss-2013-005-privilege-escalation-through-apply-roles-assignment/
FIX Disallow permissions assign for APPLY_ROLES (SS-2013-005)

See http://www.silverstripe.org/ss-2013-005-privilege-escalation-through-apply-roles-assignment/