to zero again.  Unfortunately, there appears to be a related bug where the
TX timeout is sometimes used for RX... that's OK, we'll just set them both
to zero.

Also, deal with secondary channels (ie: forwarded ports).  For now, we just
close these channels any time we get data on them.  In the future, we can
do scp/sftp pretty easily now... though neither is likely to ever work with
the sysop account due to the system password requirement.

This change ABSOLUTELY REQUIRES an updated cryptlib.  Windows guys don't
update until DigitalMan commits cl.lib or whatever it's called.