[daip] wide field clean

[larry at astro.umn.edu]

eric - hopefully i'll try the new imagr this week.  but in the
meantime, i've been using older imagr to clean a 249 field (overkill)
C configuration 74MHz data set, and noticed that the fields it
picks for subtraction do not necessarily go in order of
highest residual.  lots of fields with pretty low mins and maxes
get picked for cleaning while larger ones are still waiting.
does this make sense?  do you want mroe info?
lr