TriplesGraph.hs: added query impl for TriplesGraph graph impl.
TriplesGraph.hs: added query impl for TriplesGraph graph impl.

darcs-hash:20071002065741-db1bb-6ae62accf8f58fe7acfdeb21f529000ce432c3a9

ddssff/rdf4h,cordawyn/rdf4h,jutaro/rdf4h,LeifW/rdf4h