JarCasting
##<iron-signals>
iron-signals provides basic publish-subscribe functionality.
Note: avoid using iron-signals whenever you can use a controller (parent element) to mediate communication instead.
To send a signal, fire a custom event of type iron-signal, with a detail object containing name and data fields.
this.fire('iron-signal', {name: 'hello', data: null});
To receive a signal, listen for iron-signal-<name> event on a iron-signals element.
You can fire a signal event from anywhere, and all iron-signals elements will receive the event, regardless of where they are in DOM.
