Takes a carousel url and fires events when the carousel url changes.
const Carousel = require('ftlabs-screens-carousel');
const carousel = new Carousel(
url, // http://ftlabs-screens.herokuapp.com/generators/carousel?title=FT%20Screens%2010%2F1...
host // http://ftlabs-screens.herokuapp.com/
);
carousel.on('change', updateFrameURL);
// load the first url
updateFrameURL(carousel.getCurrentURL());