Author: Shamim Rezaie
MDL-61114 mod_assign: assignment overrides to observe group membership
http://git.moodle.org/gw?p=moodle.git;a=commit;h=a8f2981158569cbc707228837d62ad14f87adcdc
http://github.com/moodle/moodle/commit/a8f2981158569cbc707228837d62ad14f87adcdc
+ 3.5 en [groupsnone,mod_assign]