Git merges in Moodle 1.9.18 by Sam Hemelryk

commit 96d8c696ce7a192962ac1c59a0421d56b05af9c6
Author: Sam Hemelryk <sam@moodle.com>
Date:   Mon, 16 Apr 2012 08:22:50 +0800
Tag:    v1.9.18

Merge branch 'm19_MDL-32388' of git://github.com/danmarsden/moodle into MOODLE_19_STABLE