Split annotation model

Rules:
• Process for creating GRAAnnotations
o Start with GRAAnnotationModelCombined
o Change all association ends to no aggregation
o Remove all properties that have visibility protected (note that
marking may change)
o Delete classes that are entirely derived: Model, ModelReference,
IEPDReference, SchemaReference?
• Process for creating GRAIntermediateModel {Perhaps it is not worth it
to have this additional file?}
o Start with GRAAnnotationModelCombined
o Remove all *Default associations