Git commits in Moodle 2.4.x by ISHIKAWA Takayuki

commit 69101b43925b493a6802b9644436b6799801a123
Author: ISHIKAWA Takayuki <rechka_osaka@yahoo.co.jp>
Date:   Thu, 14 Jun 2012 20:29:33 +0800
Tag:    v2.4.0-beta

MDL-33757 gradebook: Adding support to sort userlist by email address