ALLHERE message and connName: change relay protocol so cookie is
included in RECONNECT message, and hostIDs are not assigned until
ALLHERE, and change host-to-game matching to use connName first but
fall back to cookie. This fixes nearly all cases failing to reconnect
after relay goes down.
change the set listened on. There's still some debugging to do but
nothing that worked before is broken. Also begin to accept unique
prefixes (e.g. g for get) for commands and attributes on the control
port. Note that relay-related code in comms seems broken now, but is
without this checkin.
scheme where cookie is used only to connect, and is replaced for
reconnects by a relay-generated name that's supposed to be unique
across all games on all relays and includes a hostname read in from
config file; relay assign non-servers' hostIDs.