Add short form to PDB edges

[Nico Matentzoglu]

[Nico Matentzoglu]

This can be tested using:

MATCH (n)-[r]-(p) WHERE NOT EXISTS(r.short_form) and NOT type(r)='SUBCLASSOF' and NOT type(r)='INSTANCEOF'  RETURN n,r,p LIMIT 10

It works on PDBL, so will close the issue.