Git commits in Moodle 2.9.3 by Tim Hunt

commit 716b0ac977a4f1c6541cd505fd64e374f91be55d
Author: Tim Hunt <T.J.Hunt@open.ac.uk>
Date:   Sun, 18 Oct 2015 23:03:29 +0800
Tag:    v2.9.3

MDL-51771 question engine: fix typo in SQL


commit 3a1c91bbe0f93607c01e0a1f884d7f95b1219e7b
Author: Tim Hunt <T.J.Hunt@open.ac.uk>
Date:   Mon, 21 Sep 2015 22:12:10 +0800
Tag:    v2.9.3

MDL-51476 questions: manual grading validation for ungraded Qs


commit 693f5eff05c12ec8b19a9993633cf807008cef13
Author: Tim Hunt <T.J.Hunt@open.ac.uk>
Date:   Fri, 18 Sep 2015 04:40:06 +0800
Tag:    v2.9.3

MDL-51375 excel output: more work to avoid invalid sheet names


commit cc895e58d4ff405466259f105154ee8ab47d114f
Author: Tim Hunt <T.J.Hunt@open.ac.uk>
Date:   Fri, 21 Aug 2015 02:12:02 +0800
Tag:    v2.9.3

MDL-51147 qtype_match: stats should cope even if Q edited badly