[ANALYZER-2285] - Integrate D3 Protovis Replacement framework into CCC
* Mixins can now provide init and postInit methods to the receiving class.
* Moved scene/index properties storage implementation to the new TemplatedElementSceneStorageMixin class
* Splitted element with children functionality to the new TemplatedElementParentMixin class
* Added the ValueTemplate class to support complex values (size, sides, stroke, ...)
* Added ParentVisual, GenericElement and AdhocTemplate classes, that are non-abstract or close to concrete.