Author: Mahmoud Kassaei
MDL-74609 Quiz: allow the displayed question numbers to be customised
http://git.moodle.org/gw?p=moodle.git;a=commit;h=2074448b3465c7feb788cbbacacdb68b2c8eb257
http://github.com/moodle/moodle/commit/2074448b3465c7feb788cbbacacdb68b2c8eb257
+ 4.2 en [edit_slotdisplaynumber_hint,mod_quiz]
+ 4.2 en [edit_slotdisplaynumber_label,mod_quiz]
+ 4.2 en [eventslotdisplayedquestionnumberupdated,mod_quiz]