Git commits in Moodle 2.5.1 by sam marshall

commit 695f6f3c232c2a01c16a978b57be20c6fb8afbf7
Author: sam marshall <s.marshall@open.ac.uk>
Date:   Fri, 17 May 2013 23:43:51 +0800
Tag:    v2.5.1

MDL-39723 Remove unnecessary queries for COURSE, SITE

commit a6683d327fbc37d586949802c60f902f0bb77b13
Author: sam marshall <s.marshall@open.ac.uk>
Date:   Wed, 15 May 2013 20:11:51 +0800
Tag:    v2.5.1

MDL-37516 Conditional activities: user field condition display fixes

commit 3a2e904098a05ab06671be595c6d9afd854fb488
Author: sam marshall <s.marshall@open.ac.uk>
Date:   Thu, 02 May 2013 22:28:17 +0800
Tag:    v2.5.1

MDL-39472 MUC: Optimise cache::get_from_persist_cache

commit aca67ae8b0d278a07cc574bdf75c7e547cefda81
Author: sam marshall <s.marshall@open.ac.uk>
Date:   Thu, 02 May 2013 01:44:55 +0800
Tag:    v2.5.1

MDL-39454 Accesslib: is_siteadmin is a bit slow