Merge pull request #11 from r3dfish/master

add index to solve ValueError: zero length field name in format
Merge pull request #12 from r3dfish/master

Adding ShipFrom information to _create_shipment
Change <ns1:Request> to <ns0:Request>

rate() now returns a valid rating for packages, now to deal with the response ...
Merge pull request #1 from benweatherman/master

This pull request solves issue #13 and gets the rate() to return rates