fix bug, add geoAsset from object
bug fix for geometry and image assets loading
reconstruct VersionViewer
design AssetWindow
design Window.AssetWin
fix UI.Window interface design
design DiffColor module, no debugging
DiffColor bug fixed
redisgn and implement the DiffColor module
	all bug fixed
	clearColor remain unimplemented
implement the clearColor interface of DiffColor module
bug fixed