Created the /objectMetadata endpoint for the API, which includes methods which interact with the OMR and OMS, but do not deal with ObjectSet instances.  Its skeleton can be found in the ObjectMetadataResource class.

Created the (empty) ObjectSetResource, which will contain the /objectSet API endpoint.  This endpoint will deal with OMR operations which utilize ObjectSet instances.

Made several objects serializable for use with the ObjectMetadataResource and ObjectSetResource classes.

~ Joshua Soles <josh@infobelt.com>