Git commits in Moodle 3.1.5 by Ankit Agarwal

commit 80e10c227871514f585b2bfe4628c2d789eae01c
Author: Ankit Agarwal <ankit@moodle.com>
Date:   Tue, 07 Mar 2017 15:13:30 +0800
Tag:    v3.1.5

MDL-57362 assign: Fix permission checks

commit b6500c619aba96bfc830f4ef7416481d7aa6bfd3
Author: Ankit Agarwal <ankit@moodle.com>
Date:   Mon, 27 Feb 2017 13:15:52 +0800
Tag:    v3.1.5

MDL-55859 assign_editpdf: cleanup htmlfile in case of errors

commit 34502102b41a2d178c4f449692b6b250d1e27d47
Author: Ankit Agarwal <ankit@moodle.com>
Date:   Tue, 21 Feb 2017 13:56:10 +0800
Tag:    v3.1.5

MDL-58032 core_user: Fix case when acting user is a visitor

commit 7b14fef5277ae611e3b91d4a6619dcba0b1922b6
Author: Ankit Agarwal <ankit@moodle.com>
Date:   Mon, 13 Feb 2017 16:01:39 +0800
Tag:    v3.1.5

MDL-55762 assignpdf: Handle errored pages better

commit cf350bc4f4a2c0d82a3c216eb6172fa42e0b3f1c
Author: Ankit Agarwal <ankit@moodle.com>
Date:   Tue, 07 Feb 2017 14:08:46 +0800
Tag:    v3.1.5

MDL-55762 assignpdf: Fix bug in phpdocs

commit 2d476195036b7f4ed8bf4d76477eca1c7403f99e
Author: Ankit Agarwal <ankit@moodle.com>
Date:   Thu, 26 Jan 2017 16:53:38 +0800
Tag:    v3.1.5

MDL-50729 events: Add user constants to events base class

commit f9465c09745e24fb8eeaf748961f8a85f6dccccd
Author: Ankit Agarwal <ankit@moodle.com>
Date:   Tue, 24 Jan 2017 20:12:40 +0800
Tag:    v3.1.5

MDL-57362 assignlib: Fix minor bug in phpdocs

commit afaeae17969689f423d3f5f03d578daf72cde71c
Author: Ankit Agarwal <ankit@moodle.com>
Date:   Tue, 24 Jan 2017 18:18:25 +0800
Tag:    v3.1.5

MDL-57296 gradelib: Fix get_hidding_effect for grade_type_none items

commit b3094c47514100b189668a0f02f2e80ce972f0a8
Author: Ankit Agarwal <ankit@moodle.com>
Date:   Sat, 14 Jan 2017 01:58:01 +0800
Tag:    v3.1.5

MDL-50729 gradelib: Regrade event should be assigned to system

commit ced9b94a04bfe07187c09efd72291b982f79bb71
Author: Ankit Agarwal <ankit@moodle.com>
Date:   Thu, 12 Jan 2017 18:26:40 +0800
Tag:    v3.1.5

MDL-57362 assignlib: Check for sep groups edge case

commit 2ba930d7bb0c09504de34275d6210cbdfb643fa5
Author: Ankit Agarwal <ankit@moodle.com>
Date:   Tue, 10 Jan 2017 15:08:29 +0800
Tag:    v3.1.5

MDL-57027 accesslib: Improve perf of sql

commit f518505d71406843b4b5bfc2fec3aa6c440e9466
Author: Ankit Agarwal <ankit@moodle.com>
Date:   Mon, 02 Jan 2017 16:56:35 +0800
Tag:    v3.1.5

MDL-57296 gradebook: Fix issue with gradebook while collapsing grades