Faster and with better UI:
- roughly halve a successful connection setup
- drop manual & temporary TCP connection before the real ZMQ one:
- it slows down the total connection time
- it's actually counted by calibre as a failed connection attempt:
after 5 consecutive failures from the same IP, calibre ignore
further connections, with no feedback to the user, except an
error trace, until the wireless server is restarted
- avoid unconditional 1s delay before checking for authentication failure
- "searching" & "connecting" (cancellable) dialogs
- stop connection on quit / restart
8fef5c1766