[DONE] Simplify send() routine to call diff() when state has changed

[DONE] Delayed ACK

[DONE] Figure out packet double-sending issue [if delay > 1/50 sec?]

[DONE] Graceful exit / server shutdown

Don't let sent_states grow without bound for long-sleeping clients

Make roaming much smoother (with error message placement)

Notify if lost contact with server

Speculative local echo

Write startup script

screen -r