Git commits in Moodle 2.4.6 by Russell Smith

commit ab2d7d4f3d863f80c0affb57f5f78b5394c6a5c6
Author: Russell Smith <mr-russ@smith2001.net>
Date:   Mon, 19 Aug 2013 18:18:57 +0800
Tag:    v2.4.6

MDL-41291 cache: Use fread to avoid race conditions

commit 5821a7c5f121bbc6b7dfd09640b917bd41e99217
Author: Russell Smith <mr-russ@smith2001.net>
Date:   Tue, 30 Jul 2013 14:00:57 +0800
Tag:    v2.4.6

MDL-40893 backup: cache question answers for performance

commit 1bdb3dcd2b6384fbb95b3629b4b28e7e461f3676
Author: Russell Smith <mr-russ@smith2001.net>
Date:   Thu, 11 Jul 2013 15:14:46 +0800
Tag:    v2.4.6

MDL-40585 backup: cache XML parent paths

commit 558f2de1b90c2d10c186cdbcceeecb4c8f11eb2a
Author: Russell Smith <mr-russ@smith2001.net>
Date:   Tue, 09 Jul 2013 18:04:09 +0800
Tag:    v2.4.6

MDL-40584 backup: Query db once per category in precheck

commit 2215cc347a0ac85e6fbba39c88b45eb4f098299e
Author: Russell Smith <mr-russ@smith2001.net>
Date:   Tue, 09 Jul 2013 08:10:17 +0800
Tag:    v2.4.6

MDL-40538 caching: Use isset for performance