Author: Davo Smith
MDL-47354 gradereport_singleview: allow choice of 'perpage' values
http://git.moodle.org/gw?p=moodle.git;a=commit;h=c6dd683cd01d6b75c46cf93fca0a53bc2a3dba4a
http://github.com/moodle/moodle/commit/c6dd683cd01d6b75c46cf93fca0a53bc2a3dba4a
+ 3.3 en [itemsperpage,gradereport_singleview]