I've long wanted common code and state that outlast a single game. The
smsproto stuff is a step in that direction, but this file will be a
place for anything new. Starting, perhaps, with a mapping of deviceID ->
addressInfo (e.g. BT name or SMS number of opponent device) that will
let me stop duplicating that stuff in every game's comms state. We'll
see. It's guarded by a compile-time flag so I can play with in on the
Linux version until ready.
