Git commits in Moodle 3.1.0 by Colin Campbell

commit 7006ab3eb7ec9632da2ff550a8cc7132691aa457
Author: Colin Campbell <colin@umn.edu>
Date:   Mon, 02 Nov 2015 23:45:36 +0800
Tag:    v3.1.0-beta

MDL-51715 lib/grade: Unit test for aggregationweight

commit 70ba1f6bcbe198094a8cf1bbc97b574e5e4b7ae0
Author: Colin Campbell <colin@umn.edu>
Date:   Sat, 10 Oct 2015 00:14:04 +0800
Tag:    v3.1.0-beta

MDL-51715 lib/grade: Zero out aggregationweight for novalue and dropped