Now $modified recurse on objects

[hendrul]

var car = {
   brand: 'Ford',
   color: 'Red',
   owner: {
      name: 'John Doe',
      age: 34
   }
}

var instance = Car.create(car);
instance.color = 'Blue';
instance.owner.name = 'Dick Harper';
console.log(instance.$modified()); //{ "color": "Blue", "owner": { "name": "Dick Harper" }}

[nateabele]

Needs a test, but the patch looks good. Thanks.