Author: Brendan Heywood
MDL-52596 assign: Add max assignment per grading page site wide setting
http://git.moodle.org/gw?p=moodle.git;a=commit;h=80989850b656664ee34a365af9e9c34dfd35c42c
http://github.com/moodle/moodle/commit/80989850b656664ee34a365af9e9c34dfd35c42c
+ 3.1 en [maxperpage,mod_assign]
+ 3.1 en [maxperpage_help,mod_assign]
+ 3.1 en [unlimitedpages,mod_assign]