Updated rasqal SPARQL demo

I've just updated my rasqal demo at http://librdf.org/query
to handle SPARQL ASK and CONSTRUCT results.  You can also ask for raw
output in which case you get the RDF/XML (graphs), VBR XML (variable
bindings) or "yes"/"no" (boolean).

The latter should change when the VBR XML format expands to encode
boolean results

Dave