Git merges in Moodle 2.0.6 by AMOS bot

commit 0d52d3366c8e0393d721b7f2d8f1bba4f6727591
Author: AMOS bot <amos@moodle.org>
Date:   Sat, 19 Nov 2011 08:31:10 +0800
Tag:    v2.0.6

Merge branch 'MOODLE_20_STABLE' into install_20_STABLE