Git merges in Moodle 2.2.3 by AMOS bot

commit 7ec66c7da8445006608db62caab8845d464f76b4
Author: AMOS bot <amos@moodle.org>
Date:   Sat, 24 Mar 2012 08:32:16 +0800
Tag:    v2.2.3

Merge branch 'MOODLE_22_STABLE' into install_22_STABLE