Working Startup and Batch Methods

Fixed the class check to make sure EasyPost is initiated.
All of the Batch functions are wrapped.

Signed-off-by: Derek Smart <dereksmart@earthlink.net>
Many Methods Added

CustomsInfo, Parcel, PostageLabel, Rate, Refund, ScanForm, Shipment, and Tracker methods added.

Signed-off-by: Derek Smart <dereksmart@earthlink.net>