Git commits in Moodle 3.1.2 by Russell Smith

commit 6311ae6d297215bdb51e075b2bfac8f531415ffc
Author: Russell Smith <mr-russ@smith2001.net>
Date:   Thu, 18 Aug 2016 19:38:12 +0800
Tag:    v3.1.2

MDL-55604 cache: Fix identifier and cacheable_object

commit ffd1a26a0b95a264bb4e569bc72cbece2d899476
Author: Russell Smith <mr-russ@smith2001.net>
Date:   Tue, 16 Aug 2016 10:12:11 +0800
Tag:    v3.1.2

MDL-55272 lib: Allow random_bytes() to return large values.

commit cdb3a0e501f61076e2bea0f5eb2db038dbc73b39
Author: Russell Smith <mr-russ@smith2001.net>
Date:   Thu, 21 Jul 2016 07:57:18 +0800
Tag:    v3.1.2

MDL-55292 performance: Allow Tideways profiler extension.