Git merges in Moodle 2.2.8 by AMOS bot

commit 1efcb6eb24728c06253aaa0c6f6f87e148bf41f6
Author: AMOS bot <amos@moodle.org>
Date:   Sat, 26 Jan 2013 08:50:51 +0800
Tag:    v2.2.8

Merge branch 'MOODLE_22_STABLE' into install_22_STABLE