PUBLIC MARKS with tags SPARQL & parser

re-wrote our original SPARQL XML results parser to use Expat, the non-validating (and fast) XML parser.

Fyzz parses the SPARQL query and generates something we decided to call an AST although it's still a bit rough for now. Fyzz understands simple triples, distincts, limits, offsets and other basic functionalities.

fyzz is a sparkling Python parser for the Sparql query language