Bump MODULE_VERSION to 5.1.2

Change-Id: I977f61a055455a589eab2121e99869f25181025f
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Merge branch 'stable' into dev

Conflicts:
	.qmake.conf

Change-Id: I88849dbc59587f40d8f36e54a400af00c1e7edc8