Fix rqsh to use a pure memory model when requested (instead of a temporary model).
Fix bug in RDF::Query::Algebra::NamedGraph->definite_variables.
Updated node classes to allow overloaded comparisions with RDF::Trine::Node::Nil objects.
Improve insertion performance in RDF::Trine::Store::Memory by keeping caching quad SHA1 hashes.
Merge branch 'master' of github.com:kasei/perlrdf