Git commits in Moodle 3.6.0 by Matt Davidson

commit 197e714dfd6a4611c9ffb327b706531051dc6492
Author: Matt Davidson <davidso1@rose-hulman.edu>
Date:   Tue, 29 May 2018 21:04:08 +0800
Tag:    v3.6.0-beta

MDL-62381 editor: Fix tinymce icons