Git commits in Moodle 2.8.8 by Jetha Chan

commit 8e074d1f69defa3bb5624c8568904d9660bf61d7
Author: Jetha Chan <jetha@moodle.com>
Date:   Fri, 17 Jul 2015 21:37:01 +0800
Tag:    v2.8.8

MDL-50868 weblib: add unit test for ruby support


commit 1e62e0c76c99279f3edb5be0e3637a2bc58de390
Author: Jetha Chan <jetha@moodle.com>
Date:   Fri, 17 Jul 2015 21:23:18 +0800
Tag:    v2.8.8

MDL-50868 weblib: add ruby support to purify_html