Add payment information.
Add payment information.

I only implemented one of several possible choices.  It happens to be the one I need, and I'm reluctant to dive into severely branch-like code at the moment.  I do plan on supporting all possible choices for this.

Search the July 2013 UPS Shipping Package XML Developers guide for "/ShipmentConfirmRequest/Shipment/PaymentInformation/" (page 92) if you want to see the reference I used.
amitej1/shipping-old,amitej1/shipping-old,amitej1/shipping-old