Moved Attean::API::Term->equals to Attean::API::TermOrVariable.
Added Attean::API::Variable->as_string method.
Added Attean::API::Bindings->mapping method.
Fixed bug in Attean::API::TriplePattern->as_quad_pattern.
Moved Attean::API::Term->equals to Attean::API::TermOrVariable.
Added Attean::API::Iterator->imap method.
Updated Attean::API::Iterator->map to allow mapping multiple values per input.
Fixed bug in Attean::SimpleQueryEvaluator handling of active graph.