update to API wrapper to version 1.0.0

changes:
 - changed class names to singular
 - Added extensive unit tests
 - added optional parameter <currency> for shipment.rates()
 - added optional parameters <size> and <page> for list method
 - added validate method to address
 - added manifest, rate, and refund classes
 - added “s” to parcel class
 - made fix to retrieve method