Bubble events on fire

Start of event bubbling very simple implementation. Component events propagate under `component.eventName`. Test sums it up:

```js
Component = Ractive.extend({
	template: '<span id="test" on-click="someEvent">click me</span>'
});

Middle = Ractive.extend({
	template: '<component/>'
});

ractive = new Ractive({
	el: fixture,
	template: '<middle/>',
	components: {
		component: Component,
		middle: Middle
	}
});

ractive.on( 'component.someEvent', function ( event ) {
	t.ok( true );
	t.equal( event.original.type, 'click' );
});

simulant.fire( ractive.findComponent('component').nodes.test, 'click' );
```

There's a second commented out test for events declared by parent on component. Need some more thought on what should happen with these.

Also no consideration for additional context beyond original event.