wif2isd.icn: Program to convert WIFs to ISDs

The following option is supported:

     -n s    name; default "untitled"

Note:  The output is an xencoded ISD.

There is a problem where there is treadling with multiple treadles
and no liftplan.  *Presumably* that treadling can be used like a
liftplan, but without, necessarily, a direct tie-up.  This problem
problem has not been addressed yet.

If there is a liftplan, then a direct tie-up is implied by the
wording in the WIF documentation.  However, that's in the interpretation
of the draft.  The tie-up produced here is the one given in the

If there is a liftplan and a treadling with multiple treadles,
the treadling is ignored.

Also not handled is the possibility of multiple shafts per thread.
This could be dealt with as for the liftplan.  The idea is that
instead of a threading corresponding to a single shaft, there are
some number of different shaft patterns, like there are liftplan
patterns.

The liftplan is represented as concatenated rows of shaft patterns in
the order they first appear.  Thus, the symbols used for them can be
reconstructed with the ISD is processed.

This program does not attempt to detect or correct errors in WIFs,
but it does try to work around some common problems.