in flattening, don't remove object nodes with existence = 0
remove junk 0..* occurrences from legacy archetypes during parsing
Fix terminology flattening so that term definitions for (say) id9.1 and id92 don't cause removal of def of id9, even though id9 may not be used directly in the (specialised) archetype.
correct various flattening errors found in CIMI archetypes
Correct logic of validity checking on occurrences of proxy references.