o Evaluate centroid in detection phase so that evaluation can
  include quantities based on distance from centroid.
o Kron magnitudes
o Add partial pixel
o What to do about contaminating objects in the apertures.

TODO

o MapIO - match coordinates for sky fit
o match object mask as part of aceall when outobjmask is given
o reorganize to remove xap,yap,etc from detection phase
o errors in ra/dec and mags
