Board renders, but only when touched. Tray and scoreboard skipped for
now. Lots of changed still to go, and some asserts added where I didn't
want to stop to solve a compile problem.
the case where one of several guests wants to rematch is a hard
problem for later.) Requires passing old-style relayIDs (connname plus
device index) when devIDs aren't available, which they may not always
be.