Git commits in Moodle 3.3.6 by Nick Phillips

commit be17ced74793c8553c3d93fba3cd1ff37f6087ea
Author: Nick Phillips <nick.phillips@otago.ac.nz>
Date:   Mon, 15 May 2017 07:55:49 +0800
Tag:    v3.3.6

MDL-55532 gradebook: fix grade export to include category names