Avnet / Mbed 2 deprecated WNCInterface_M2XMQTTdemo

The ARM mbed MQTT client library is used to send/receive data to/from AT&T's M2X service (https://m2x.att.com/) using the AT&T Cellular IoT Starter Kit which is sold by Avnet (http://cloudconnectkits.org/product/att-cellular-iot-starter-kit).

Dependencies:   M2XMQTTClient WNCInterface mbed-rtos mbed minimal-json minimal-mqtt-JMF