Extensible select and enumeration types

and their elements in schema MECHANICAL_DESIGN_SHADED_PRESENTATION_MIM taking into account BASED_ON types


 external_identification_item - EXTENSIBLE GENERIC_ENTITY SELECT
          document_file
          trimmed_curve

 groupable_item - EXTENSIBLE GENERIC_ENTITY SELECT

 identification_item - EXTENSIBLE SELECT
          document_file
          representation
          shape_representation

 invisible_item - EXTENSIBLE GENERIC_ENTITY SELECT
          presentation_layer_assignment
          representation
          styled_item

 presented_item_select - EXTENSIBLE GENERIC_ENTITY SELECT

 versionable_item - EXTENSIBLE SELECT
          document_file
          shape_representation