Git commits in Moodle 3.4.2 by Tim Hunt

commit 5678028de75856e920333f7d0659f30b8b3e3d1d
Author: Tim Hunt <T.J.Hunt@open.ac.uk>
Date:   Tue, 06 Feb 2018 20:09:43 +0800
Tag:    v3.4.2

MDL-61366 setuplib: safely construct the ajax renderer when needed


commit ffb43a83b0823dd72fb3c5d96027fc493ab9fbb8
Author: Tim Hunt <T.J.Hunt@open.ac.uk>
Date:   Thu, 21 Dec 2017 01:55:57 +0800
Tag:    v3.4.2

MDL-61077 question stats: make calculations more robust