I agree with changing this away from `this.content`. I want to get in the habit of using plain old javascript objects as the event data, so we don't have to break the API as much to pass more info to event handlers.

So I'd prefer this as

    this.$el.trigger('removeContentView.hub', { contentView: this });

That way more things can be added to the POJO later, and handlers aren't expecting to get an object there that is `instanceof ContentView`