Git commits in Moodle 2.5.6 by Ashley Holman

commit fd0d236dce9c1d4ae31d517fc12b298b17c5d16d
Author: Ashley Holman <ashley@netspot.com.au>
Date:   Mon, 20 May 2013 10:45:29 +0800
Tag:    v2.5.6

MDL-39740 grade: Fix grade_item::add_idnumber strict type checking