Git commits in Moodle 3.6.x by Dan Poltawski

commit 292df9f613f986c664669174bdd4fbd2feabce16
Author: Dan Poltawski <talktodan@gmail.com>
Date:   Fri, 31 Aug 2018 18:35:12 +0800
Tag:    v3.6.0-beta

MDL-48846 filter: Stop reffering to invalid moodle.org/download/mimetex