• (Addition) Add INVOKE function expression to allow representing
  IRI-defined functions.
  
• (Addition) Added Attean::API::Algebra methods blank_nodes and
  subpatterns_of_type.
  
• (Addition) Added Attean::API::SimpleCostPlanner.
  
• (Addition) Added Attean::API::UnionScopeVariablesPlan role to handle
  common computation of in-scope variables (Github issue #38).
  
• (Addition) Added Attean::Algebra::Sequence class.
  
• (Addition) Added AtteanX::API::JoinRotatingPlanner role.
  
• (Addition) Added SPARQL parsing support for RANK operator (Github issue
  #35).
  
• (Addition) Added initial algebra and plan support for group ranking
  (Github issue #34).
  
• (Addition) Added simple SPARQL HTML serializer (ported from
  RDF::Endpoint; Github issue #27).
  
• (Addition) Added simple SPARQL serializer implementation (Github issue
  #36).
  
• (Update) Added ability to turn some query algebras into SPARQL token
  interators.
  
• (Update) Compute in-scope variables in Attean::Plan::Quad instead of
  relying on calling code (Github issue #39).
  
• (Update) Ensure query plan costs are integers, fixing a bug when running
  on perl with long doubles (#42).
  
• (Update) Fixed attean_query to support custom output serializers.
  
• (Update) Fixed bug in Attean::Algebra::Project->in_scope_variables.
  
• (Update) Fixed bug in t/http-negotiation.t that caused false failures
  when negotiation led to the Canonical NTriples serializer.
  
• (Update) Fixed mis-named method call in AtteanX::Store::Memory.
  
• (Update) Improve error messages in query planning code (manual patch
  from #41).
  
• (Update) Improve serializer negotiation to support multiple classes that
  handle the same media type.
  
• (Update) Ported RDF::Query SPARQL parser to Attean.
  
• (Update) Refactored query planner to separate IDP code from the core
  planning code.
  
• (Update) Renamed Attean::API::Planner to Attean::API::QueryPlanner and
  re-organized planning code.
  
• (Update) Update Changes metadata handling to use
  Module::Instal::DOAPChangeSets (Github issue #25).
  
• (Update) Updated Attean::Algebra::Join to be n-ary, not binary.
  
• (Update) Updated attean_query to use the native SPARQL parser.