
20101222 : EAM

  continuing work on psphot stack.  Some notes:

  * visualization now has duplicate image display calls
  * visual needs to do a better jobs scaling the smoothed, subtracted images.
  * the fit radius for the convolved images should be a bit bigger than the unconvolved one
  * *** fitRadius vs apRadius ***
    I have been using 'markVal' to define the valid pixels for different operations
    I think this has been inconsistent.  

    ** Have pmSourceMagnitudes apply the defined apRadius on the fly
       when measuring aperture photometry

    ** Set the fitRadius and keep it until redefined?

    ** RadialApertures does not use the marked region?
