Per-country feature to use short values for regions

[dlong500]

I think it would be great to add some props to the RegionDropdown where a list of countries could be specified that override the labelType and valueType props only for those countries.

For example, you could have something like valueTypeCountriesShort={['US']} as well as labelTypeCountriesShort={['US']} to make only the United States show regions using short codes even if the overall setting for valueType and labelType is "full". I don't really know if any other countries use short codes for addresses, but in America it is standard to use short codes for the states, so it would be helpful to have the option of using short codes for American states but full values for all other country regions.

[leocifer]

+1