function: wmfilter_corslice -- wfilter one slice
keyboard equivalents: none

Run the wmfilter (anisotropic 5x5x5 filter) on
one coronal slice and put the output into
imageset2.  To compare simple truncation to the
wmfilter, set white hi and lo truncation, do
WMTRUNC, and use COMPARE.  Default is TRUE for
both $spackleflag and $flossflag (see extended
panel).
