Include reference_id in DataResponse in PaymentMethodResponse in Payment.

Include external_reference_id in DataResponse in PaymentMethodResponse in Payment.

Include external_resource_url in DataResponse in PaymentMethodResponse in Payment.

Fix is_same_bank_account_owner type. Now it is bool instead of string.

Include sub_type in PointOfInteractionRequest in Payment.

Include sub_merchant in ForwardData in Payment.

Fix differential_pricing_id type. Now it is int instead of string.

Solution for issue 56.

Initial release