Git merges in Moodle 2.5.0 by AMOS bot

commit a1327196eedd7223fe60eec6bbfbe74a15be6ad8
Author: AMOS bot <amos@moodle.org>
Date:   Tue, 14 May 2013 08:37:41 +0800
Tag:    v2.5.0

Merge branch 'master' into install_master