Call .change() trigger when updating values of billing address from delivery address

I put a .change() trigger on the billing-zone select input and discovered that when the 'My billing information is the same as my delivery information.' checkbox is selected, my .change() trigger was not triggering when the delivery address data was copied into the billing address fields.

The only time the trigger in not called is during the initial load of the delivery data into the billing fields. If the 'same as' checkbox is not selected, my .change() trigger on billing-zone worked correctly, and once the 'same as' checkbox is selected, changing the delivery-zone select triggers my .change() trigger on billing-zone correctly.

Attached is a patch that adds a call to .change() where the data from the delivery address fields is copied into the billing address fields.