Fixed Issue #5

Might not be the best way to do so but it kinda works.   Here's a PLNKR that demonstrates.  http://plnkr.co/edit/MjKBW2TpASsMo5xoui0Z?p=preview

One thing it doesn't handle is if the model is set to null.  You can see I changed the clear() function to set the selectedCars = [] instead of selectedCars = null.  Anyways just submitting this to help jumpstart your fix; I'm sure you'll know a better way to do so.