Git merges in Moodle 3.1.15 by Andrew Nicols

commit 6776687817588a89de4795f80db9b3fade36f01c
Author: Andrew Nicols <andrew@nicols.co.uk>
Date:   Tue, 16 Oct 2018 08:57:36 +0800
Tag:    v3.1.15

Merge branch 'MDL-63421_31' of git://github.com/stronk7/moodle into MOODLE_31_STABLE


commit 8ee12efa228ce2cd64d00a576e1bcf40785e4ee5
Author: Andrew Nicols <andrew@nicols.co.uk>
Date:   Tue, 25 Sep 2018 09:18:27 +0800
Tag:    v3.1.15

Merge branch 'MDL-63346_31' of https://github.com/stronk7/moodle into MOODLE_31_STABLE