PersistableObject
      (ctor) PersistableObject()
      PersistableType TypeID( get; )
      void Deserialize( PersistanceReader ip )
      virtual void DeserializeAttributes( PersistanceReader ip )
      virtual void DeserializeChildren( PersistanceReader ip )
      void Serialize( PersistanceWriter op )
      virtual void SerializeAttributes( PersistanceWriter op )
      virtual void SerializeChildren( PersistanceWriter op )