Apache Taverna Engine Reference Types 3.1.0-incubating

Implementations of certain SPIs to provide a core set of functionality for the reference management framework. This includes ExternalReference implementations to reference data held in local files and URLs along with the appropriate translate / publish logic. Implementations in this package are tied only to the API, although certain metadata files such as hibernate mappings are also included where appropriate (these will be silently ignored if using a backing store that is not hibernate based)