The internal unique id should not be needed, the pid is unique enough :)
Also this can allow starting dooms externally without having to pass an id
parameter that's not already in use. The externally started doom sends its
pid with the DoomReady message and the controller can add a new entry if it
needs to. Of course the controller will not be able to kill() these
externally started dooms.
When usleep()'ing in doomsim it misses most of the quit messages. I think
it's because the controller spams RunDoom all the time and the quit
messages get discarded while doomsim is sleeping.
