mqtt.deviceid - defines a unique device id
mqtt.setup - setup the broker URL, must be a domain name, IP addresses probably not working yet
mqtt.connect - connect to broker and keep connection alive
mqtt.disconnect - disconnect
mqtt.subscribe - subscribe a topic
mqtt.unsubscribe - unsubscribe topic
mqtt.publish - send data to the broker
You can subscribe multiple topics at a time but after a temporary disconnection from the server only the last subscribed topic will be automatically subscribed to again.