Transform updates synched with QChangeArbiter

Transform monitor changes of each of its AbstractTransform objects.
On a change, it notifies the QChangeArbiter. The QChangeArbiter tells
the associated RenderNode about the change. The RenderNode updates its
localTransform matrix.

Small typo correction appendTransform instead of appendTransfrom.

Change-Id: I8613cda1b3c7b7211722f78585ac75736528f86a
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>
Handle Component property reference changes

A follow up patch with a reworked Entity / Component
composition will follow.

Change-Id: I7d89fc660f933b43345755529041a9909d1f83a5
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>
Added QmlEntity

QmlEntity is a subclass of Entity.
It contains a QmlListProperty of Components. It properly
separates the C++ from Qml.

Change-Id: I8004943e3a98fb3211309a38e022be71560f9951
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>
Hooked up QmlEntity

The simple_qml has been updated to use QmlEntity.
Only QmlEntity is instanciable on the Qml side. With the
use of a QmlListProperty we can easily monitor component changes.

Change-Id: Ie59258767450e842093bd76b0f55dfe31724c752
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>