Added support for receiving CONNACK
Added support for receiving CONNACK

njh/mqtt-sn-tools,adamrenner/mqtt-sn-tools-contiki,adamrenner/mqtt-sn-tools-contiki,njh/mqtt-sn-tools,MichalFoksa/mqtt-sn-tools,MichalFoksa/mqtt-sn-tools,adamrenner/mqtt-sn-tools-contiki