that all connectivity was with relay and over streaming sockets (since
BT is using l2cap's datagram-style sockets.) With this checkin, a full
robot-vs-robot game is possible with palm as host and linux as client.
Linux as host isn't started yet.
message is length plus data. Use non-deprecated gtk select-like
function. With these changes can play full games through the relay on
gtk. Untested on ncurses but probably broken.