Author: Nathan Nguyen
MDL-80984 mod_assign: penalty implementation
http://git.moodle.org/gw?p=moodle.git;a=commit;h=cd239dd1c34d51213ec05df5fe89bc4de5937cca
http://github.com/moodle/moodle/commit/cd239dd1c34d51213ec05df5fe89bc4de5937cca
+ 5.0 en [gradepenalty,mod_assign]
+ 5.0 en [gradepenalty_help,mod_assign]
+ 5.0 en [overriderecalculatepenalty,mod_assign]
+ 5.0 en [penaltyduedatechangemessage,mod_assign]