Fixed RDF::Literal::Double instantiation from "INF"^^xsd:double, "-INF"^^xsd:double, and "NaN"^^xsd:double.
Fixed RDF::Literal::Double instantiation from "INF"^^xsd:double, "-INF"^^xsd:double, and "NaN"^^xsd:double.

The following all now work as expected:

    RDF::Literal("INF", :datatype => XSD.double).to_f   #=> Infinity
    RDF::Literal("-INF", :datatype => XSD.double).to_f  #=> -Infinity
    RDF::Literal("NaN", :datatype => XSD.double).to_f   #=> NaN

jcoyne/rdf,ninjapanzer/rdf,PerfectMemory/rdf,ruby-rdf/rdf