
20090611 : adjusting things to allow the readnoise to be an image map for each cell

  * pmReadoutSetVaraince : when variance is created, we are suppling a single CELL.READNOISE value -- change this to an optional image (carried through concepts?)

  I need to:

  * define a format for the readnoise map (image map in SPLIT/MEF format?)
  * load the readnoise map

  * supply the map for each cell to the pmReadoutSetVariance (pointer to ppImageMap?)
    pmReadoutSetVariance -> add psImageMap to API (also pmReadoutGenerateVariance)

  * add recipe information to define the source of the READNOISE info.

