Allow context change after element has been rendered

[justinbmeyer]

<div data-control='controls/widget'>
      {{#todos}}
        <div>

        </div>
      {{/}}
</div>

// in controls/widget
can.Control({
  init: function(element, context){
    context.todos = Todos.findAll()
  }
})

This is very angular / knockout. Somehow, I want to be able to not call the div's "internal" function until after the div has been created. Once the div is created, I'll create the control/widget instance on it, passing the context as options to the control. The control can add items to the context. After the control is created, it will run the "internal" function with the new context.

If #179 works, the internal function to {{#todos}} will also wait until everything has finished rendering.

[justinbmeyer]

canComponent branch with can.view.Scope allows this kind of thing.