o Better CCP/WARN Reset diagnostics.
o After we've sent a REQ and before we've received an ACK, we drop
  incoming compressed data and send another REQ.
o Before sending an ACK, re-sequence all pending PRI_NORMAL data in
  the modem queue so that pending packets won't get to the peer
  *after* the ResetAck.
o Send ACKs with the `identifier' from the REQ frame.
o After we've received a correct ACK, duplicate ACKs are ok (and will
  reset our history).
o Incorrect ACKs (not matching the last REQ) are moaned about and dropped.

o Calculate the correct FCS after compressing a packet.  DEFLATE
  *may* produce an mbuf with more than a single link in the chain,
  but HdlcOutput didn't know how to calculate the FCS :-(
o Make `struct fsm'::reqid a u_char, not an int.
  This fix will prevent us from sending id `255' 2,000,000,000 times
  before wrapping to `0' for another 2,000,000,000 sends :-/
o Bump the version number a little.

I can txfr a 1.5Mb kernel over a (rather bad) null-modem
cable at an average of 21679 bytes per second using rcp.

we never lose packets and therefore never have to reset!