Git commits in Moodle 3.1.0 by Niclas Tollstorff

commit 7b96ffb0449b6f1b458a154fa262fe9e292ecf5f
Author: Niclas Tollstorff <niclastollstorff@gmail.com>
Date:   Thu, 11 Feb 2016 10:23:22 +0800
Tag:    v3.1.0-beta

MDL-53072 group: added 'only active' option when auto-creating groups