Git commits in Moodle 2.4.2 by Howard Miller

commit 3bcf80e9f2ac4bbc1c8cfc1df3c08f7b0a849162
Author: Howard Miller <howard@e-learndesign.co.uk>
Date:   Tue, 05 Feb 2013 16:15:43 +0800
Tag:    v2.4.2

MDL-37797 HTML block: add contextid to block_positions query and make it more unique.