Extensible select and enumeration types

and their elements in schema AREA_2D_XIM taking into account BASED_ON types


 characterized_product_definition - EXTENSIBLE SELECT
          product_definition
          product_definition_relationship

 constructive_element_select - EXTENSIBLE GENERIC_ENTITY SELECT
          axis2_placement
          curve
          point_select
          surface

 identification_item - EXTENSIBLE GENERIC_ENTITY SELECT
          shape_representation