Git merges in Moodle 2.1.3 by AMOS bot

commit 81b24b17cf054b9a3794c7f377ea0ce1cb02b763
Author: AMOS bot <amos@moodle.org>
Date:   Sat, 19 Nov 2011 08:31:04 +0800
Tag:    v2.1.3

Merge branch 'MOODLE_21_STABLE' into install_21_STABLE