Xsd does not contain reference types and identity types for all domain entities and associations

MetaEd generates reference types for all domain entities and associations. 2.0 Final xsd does not contain reference types for all domain entities and associations. 38 identities and reference types are missing.

This causes implementations that need to define extensions that reference these domain entities to define the reference types for core Ed-Fi entities.

No anticipated impact outside of Core xsd. Provides benefit of ease of extension for these types as part of core.