PICTFormat: set bits per pixel

Bits per pixel were not being set in pixt format. This has been
corrected.
NativeQTFormat: set bits per pixel

Bits per pixel were not being set in the NativeQTFormat. This has been
corrected.
NRRDFormat: Set bits per pixel

Bits per pixel were not being set in the NRRDFormat. This has been
corrected
WIP: CellImg