If tasks are run in interactive mode have them write out a geometry file
at the same time they write out a results file. This gets around the
problem of the object list being dynamic in the version of xapphot.
This avoids the problem of mixed geometries causing trouble for the output
format as well.  Details to be worked out later.

Divide commands into command subsets with a specific letter as prefix, e.g.
f for files i for image. Try to make the first three letters of a command
define it uniquely.
