Distinguish international and domestic USPS calculators because service codes returned from usps api are not mutually exclusive
Update USPS shipping rate names and fix a bug in checking max weight for countries.
Add USPS Standard Post and USPS Global Express Guaranteed (GXG)
Use a decimal for unit_multiplier
Merge branch '2-2-nemo-stable' of github.com:godaddy/spree_active_shipping into 2633
Merge branch '2-2-nemo-stable' of github.com:godaddy/spree_active_shipping into 2633
Merge pull request #2 from godaddy/2633

2633