FLUID-5201: Composite panel less aggressive

The composite panel will be less aggressive in terms of rebasing/surfacing subcomponents. will only work with fluid.prefs.panel type subcomponents.
FLUID-5202: initial model for subpanels

onCreate of the subpanel, it will now source its initial model value from its parent composite panel. All subsequent model changes will be handled by the model relay.
FLUID-5202: expanded valuebinding rebasing

valuebinding fields within a selection object in the renderer tree are now properly rebased.
FLUID-5200: handling parentRelativeID's

rebasing parentRelativeID's
Merge remote-tracking branch 'justin/FLUID-5200' into FLUID-5190
FLUID-5203: Added a unit test.