Bump MODULE_VERSION to 5.3.1

Change-Id: I966aae81ff0901ab81b96e0e69ffcbfe2acb7ea1
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Merge remote-tracking branch 'origin/stable' into dev

Conflicts:
	.qmake.conf

Change-Id: I7a53a0601021edff1cb5acb3e2f7924512a27e3c