Git commits in Moodle 3.1.0 by Pavel Sokolov

commit 4dab33b586bb23fd093748c9a7e09595caeb0f93
Author: Pavel Sokolov <pavel.m.sokolov@gmail.com>
Date:   Thu, 05 Dec 2013 21:00:34 +0800
Tag:    v3.1.0-beta

MDL-43069 assign: prevent JS error on grading table