I'll clean that up later.  Also corrected a mistake introduced by the
previous reformatting: an 'else' belonging to a 'for' was accidentally
reindented to belong to the 'if' inside the 'for'.  Note that the
module uses inconsistent indentation -- most code is indented with 8
spaces, but some of the reformatted code uses 4 spaces.  I'll fix this
later in the promised cleanup pass.

big-endian machines.  This is done by directing the struct module's pack
and unpack methods to treat the data always in bin endian format.
This has been tested on irix (big endian) and solaris x86 (little endian)
but not yet on the mac.

Note: binhex works, hexbin does not work yet.