Eclipse Mosquitto™ 1.5.5

Security:

- If `per_listener_settings` is set to true, then the `acl_file` setting was

  ignored for the "default listener" only. This has been fixed. This does not

  affect any listeners defined with the `listener` option. Closes #1073.

Broker:

- Add `socket_domain` option to allow listeners to disable IPv6 support.

  This is required to work around a problem in libwebsockets that means

  sockets only listen on IPv6 by default if IPv6 support is compiled in.

  Closes #1004.

- When using ADNS, don't ask for all network protocols when connecting,

  because this can lead to confusing "Protocol not supported" errors if the

  network is down. Closes #1062.

- Fix outgoing retained messages not being sent by bridges on initial

  connection. Closes #1040.

- Don't reload auth_opt_ options on reload, to match the behaviour of the

  other plugin options. Closes #1068.

- Print message on error when installing/uninstalling as a Windows service.

- All non-error connect/disconnect messages are controlled by the

  `connection_messages` option. Closes #772. Closes #613. Closes #537.

Library:

- Fix reconnect delay backoff behaviour. Closes #1027.

- Don't call on_disconnect() twice if keepalive tests fail. Closes #1067.

Client:

- Always print leading zeros in mosquitto_sub when output format is hex.

  Closes #1066.

Build:

- Fix building where TLS-PSK is not available. Closes #68.