Author: Shamim Rezaie
MDL-61114 mod_assign: assignment overrides to observe group membership
http://git.moodle.org/gw?p=moodle.git;a=commit;h=2451ef2ba5c9ed0d2796b4affc7d96b0729b9bef
http://github.com/moodle/moodle/commit/2451ef2ba5c9ed0d2796b4affc7d96b0729b9bef
+ 3.6 en [groupsnone,mod_assign]