nested attr() call on a model with List attributes blows away existing List

[makebbekus]

#151 fixed this issue with simple objects, but the test here shows it's still a problem when the attributes plugin is involved.

The failure is the same as before in that a new list (with a new _cid) is made.

I'm not quite sure how to address this one, so I'm just submitting the failing test.

Thanks!

[daffl]

Yes, this is because of the attributes plugin. When setting members, EmptyListTest.User.models will be called, which returns a new Observable list every time.

I think we could change .models and the attributes plugin so that it removes all elements and adds the new ones if the current attribute is a can.Observe.List already. That should solve the problem right?

[daffl]

Ok, I pushed a fix. The attributes plugin now clears and updates an existing list, your test case is passing.

[cohuman]

Awesome, thanks! This should fix our problem. We'll check it out.