Fix scope sucking

@xcoderzach @tobowers @yaymukund 

So.... scoping update on model changes was broken....

```javascript
//Scope modifier spec
    it("should be able to access a model after relative scope", function() {
      this.thing.set('item', new Model({name: 'Lebron'}));
      this.model.set('item', new Model({name: 'Lebron'}));
      expect($("#itemName").html()).to.be("Lebron");
    });
```

This would fail... ie., it would not actually update the model

Need to work on this more but wanted to update you to this being an issue (even in current brief end-dash) and to let you have a chance to glance at this in case you had feedback. I will more working on this more at some point :smile: