Added ImgExt1.java

	* We need to check whether we serialize an ImgView or an Img in ImgExt
	* What may go wrong:
		** Seralize with flatIterationOrder (ImgView on CellImg)
		** Deserialize with CellIterationOrder
Minor Code-Cleanups

	* Formatting
	* Deprecation of unused externalizers
Added ImgExt1