HTTPS support on Pico!

At the moment there's nothing in there for certificates at all, so I'd have to add that.

But for now I think you can get away without modifying the MQTT lib - it was designed to work over things other than network sockets unless someone wanted to (for instance) use some other kind of radio:

  var mqtt = require("MQTT").create();
  mqtt.on('connected', function() {
    mqtt.subscribe("test");
  });
require("tls").connect("mqtt://whatever:1234", function(res) {
  mqtt.connect(res);
});