Update to WorldCat Metadata API

Based on feedback from the library developer community, the latest release of the WorldCat Metadata API includes new operations for validating records. This added functionality allows clients of the WorldCat Metadata API to verify the validity of records used for creation and update purposes within the API. By pre-validating records, clients can more easily display issues with records to the user for corrections before final submission to WorldCat. Complete details on the validation operations is available in the API documentation.