AGJS-47 add MQTT over Web Sockets notifier adapter

Created a new branch for AGJS-47 (add MQTT over Web Sockets notifier adapter).

You can find the QUnit tests in the integration repo: https://github.com/tolis-e/aerogear-js-integration
Execute ./servers/activemqtest/server.sh and then open the tests/notifier/mqttws.html file in a browser. The problem is that it doesn't work in phantomjs for some reason after updating to activemq-5.9.0 (version which supports MQTT over Web Sockets).