Shipping Address On Pre-orders.

When a parent returns to complete their pre-order that's in their cart with $0 for amount need to have a shipping address for 2 reasons:

1. Shipping and billing addresses aren't always the same. And I use the fullfilled order to ship the prints out since there's no link to the original order#

2. On the orders page I look at the address column to determine if it's a digital order or print order since print orders always have shipping addresses I then mark the digital as complete. Not seeing a shipping address, I've now neglected to print 2 print pre-orders because of this I inadvertantly marked them as complete.

For future upgrade, it would be great if the original pre-order that is generated is somehow linked to the new order that is generated when the parent's return to fill their order. Currently having 2 separate order numbers does not let me know if a customer has fullfilled the order yet. Either make the original order marked filled of merge the 2 orders together once it is fulfilled.