Bump MODULE_VERSION to 5.3.1

Change-Id: Ic12bff4a564117f7e566e8880ed66046be5ea07d
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Merge remote-tracking branch 'origin/5.3' into dev

Conflicts:
	.qmake.conf

Change-Id: Id4d3d030c5cb609a4b7ad03c5496a9a5625d46c5