raise exception when trying to add/query for bnodes with sparql(update)store. fixes #276
raise exception when trying to add/query for bnodes with sparql(update)store. fixes #276

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