Author: Shamim Rezaie
MDL-61114 mod_assign: assignment overrides to observe group membership
http://git.moodle.org/gw?p=moodle.git;a=commit;h=211f6809b919267852367d7279efdcf1c020564c
http://github.com/moodle/moodle/commit/211f6809b919267852367d7279efdcf1c020564c
+ 3.7 en [groupsnone,mod_assign]