• (Addition) Add a size estimate attribute to Attean::Plan::Iterator (#90
  from KjetilK).
  
• (Addition) Added Attean::Plan::Iterator for cases where there is too
  much data for Attean::Plan::Table (#88).
  
• (Update) Add ability for parsers to construct lazy IRIs.
  
• (Update) Add type checking to serializeiter* methods.
  
• (Update) Added Attean::ListIterator->size method (#89).
  
• (Update) Fix cases where result iterators were constructed without a
  variables list.
  
• (Update) Improve error message generated for some SPARQL syntax errors.
  
• (Update) Update Attean::FunctionExpression to canonicalize ISURI to
  ISIRI.