RM4 Mini support

[ryeger]

I switched my old RMMINI (RM Mini3 as called in Broadlink's site) which worked fine, to the new smaller model RM MINI4.
mqtt,py does not recognize it - it says "DEBUG Connected to 'Unknown' Broadlink device at '192.168.2.138' (MAC 16:6a:5e:b0:43:a0) and started listening to MQTT commands at 'broadlink/#'"
and in mqtt client I see "Adios!"

Please add support for this model, as it is smaller, and also has humidity and temperature sensing
Thanks