DDSXTY14 — Allow documentation and licensing to be associated with types

When creating a datamodel it is imortant to be able to document various elements (types, members, enumeration literals) this documentation belong ti the TypeSystem model as it is something that needs to me representable in all TypeRepresentations.

Likewise data-types defined in teh TypeSystem may have associated licensing descriptions that need to be expressed in the various type representations.

XTYPES should define these concepts and specify how that are represented.