Git commits in Moodle 3.6.x by Nathan Nguyen

commit 5a1de3de31cba549ce13be06734cee56abd01b57
Author: Nathan Nguyen <nathannguyen@catalyst-au.net>
Date:   Mon, 24 Jun 2019 14:19:44 +0800
Tag:    v3.6.6

MDL-65555 mod_lesson: fix group override backup and restore

commit 6cb12d596fb6cb0047fbda039bdebcc399a49710
Author: Nathan Nguyen <nathannguyen@catalyst-au.net>
Date:   Mon, 24 Jun 2019 13:49:44 +0800
Tag:    v3.6.6

MDL-65555 mod_quiz: fix group override backup and restore

commit 47b4f219949da035ed7eb19620b2b255fb0b3c80
Author: Nathan Nguyen <nathannguyen@catalyst-au.net>
Date:   Fri, 15 Feb 2019 13:20:14 +0800
Tag:    v3.6.4

MDL-63263 tool_recyclebin: Apply automated backup setting

commit 923641f71ce213f8f793550a16373652ee976431
Author: Nathan Nguyen <nathannguyen@catalyst-au.net>
Date:   Mon, 20 Aug 2018 10:56:34 +0800
Tag:    v3.6.0-beta

MDL-62319 Assign: Grading interface is broken when using iOS 11.3 devices