Code changes for new schema

This directly affects the following formats:

BD, BaseZeiss, BioRad, Deltavision, FEITiff, FV1000, Gatan, HamamatsuVMS, InCell, Ivision, LIF, Leica, LeicaSCN, MIAS, NikonTiff, Prairie, SIS, SimplePCITiff, Slidebook, SlidebookTiff, Volocity, ZeissCZI, ZeissLSM

And also the sifio MetadataConverter which may affect others.

This PR is for testing at the moment.