Git commits in Moodle 3.6.5 by Tim Hunt

commit 81b386b9ae74b2de683fde2fe0a28656d1c78c39
Author: Tim Hunt <T.J.Hunt@open.ac.uk>
Date:   Wed, 19 Jun 2019 00:14:37 +0800
Tag:    v3.6.5

MDL-57884 quiz: autosave should not send the value of submit buttons

commit c82b6e01b15f418ffcac5f5272e5c609f8e0ed22
Author: Tim Hunt <T.J.Hunt@open.ac.uk>
Date:   Fri, 07 Jun 2019 02:41:34 +0800
Tag:    v3.6.5

MDL-65864 question engine: fix re-saving a new usage

commit 697de172a1b46d9f14bdef482d813d94098e41c1
Author: Tim Hunt <T.J.Hunt@open.ac.uk>
Date:   Wed, 29 May 2019 20:38:41 +0800
Tag:    v3.6.5

MDL-65731 quiz manual grading: fix ambiguous order by idnumber

commit 0925ecdbd4b4ed6d82eab91364d870835bd1a418
Author: Tim Hunt <T.J.Hunt@open.ac.uk>
Date:   Fri, 17 May 2019 22:35:54 +0800
Tag:    v3.6.5

MDL-55197 filter_multilang: handle 'en' as parent lang better

commit 0bff3507f74fb143cbddf914fb68abad8abf784d
Author: Tim Hunt <T.J.Hunt@open.ac.uk>
Date:   Fri, 17 May 2019 22:18:06 +0800
Tag:    v3.6.5

MDL-55197 filter_multilang: move preg_callback fn into class

commit 957e78388a398dc162ae007075eb97e17eb6b290
Author: Tim Hunt <T.J.Hunt@open.ac.uk>
Date:   Fri, 17 May 2019 19:22:19 +0800
Tag:    v3.6.5

MDL-65636 filter_multilang: add some basic unit tests