Git commits in Moodle 3.1.16 by David Monllao

commit 6f41a2c3185b3c6e2f6a8b75bd05c648016942fb
Author: David Monllao <davidm@moodle.com>
Date:   Tue, 20 Nov 2018 19:55:06 +0800
Tag:    v3.1.16

weekly release 3.1.15+