displays: on disconnect, don't send an old display on message bus

A display could have changed its characteristic on disconnect. Only send
an up-to-date copy in this case. Maybe there is a better way of doing
this by systematically refreshing stuff we send on the message bus.
receiver: try harder to reconnect on failure

It is not quite clear if a limited number of reconnect attempts mean we
don't reconnect at all after this number of attempts (the source code
seems to reset the logic). Therefore, just bump the number of attempts
to infinity with a maximum delay of 1 minute and reload in case of
catastrophic failure.