Itemevent argz

This change adds consistency to our callbacks for children events.

When you call `trigger` from a Backbone Event'ed object, you pass in the name of the event, then any additional arguments.

`myObj.trigger('some:event', argOne, argTwo);`

Registered callbacks do not get the name of the event as the first argument. They only get `argOne` and `argTwo`.

Our collection view code set up a `listen`-like system where we listened to events on the children and triggered callbacks. These callbacks were getting all of the arguments – even the name of the event. This was inconsistent & is gone now.

This fixes #1154