Here's a fix for fax2ps that corrects behaviour for non-Letter paper
sizes. It fixes two problems:
Without scaling (-S) the fax is now centered on the page size specified
with -H and/or -W. Before, fax2ps was using an obscure and practially
useless algorithm to allocate the image relative to Letter sized paper
which sometime sled to useless whitespace on the paper, while at the
same time cutting of the faxes printable area at the opposite border.
Second, scaling now preserves aspect ratio, which makes unusual faxes
(in particular short ones) print properly.
