added term instanciation dictionary and added use of isinstance instead of type (better performance)
added term instanciation dictionary and added use of
isinstance instead of type (better performance)

RDFLib/rdflib,armandobs14/rdflib,marma/rdflib,yingerj/rdflib,ssssam/rdflib,RDFLib/rdflib,yingerj/rdflib,avorio/rdflib,dbs/rdflib,RDFLib/rdflib,marma/rdflib,yingerj/rdflib,RDFLib/rdflib,dbs/rdflib,avorio/rdflib,avorio/rdflib,avorio/rdflib,armandobs14/rdflib,armandobs14/rdflib,dbs/rdflib,ssssam/rdflib,marma/rdflib,marma/rdflib,ssssam/rdflib,armandobs14/rdflib,yingerj/rdflib,ssssam/rdflib,dbs/rdflib