[sparql] more SPARQL 1.1 features

the ongoing work is appreciated, as always!

this PR adds some more features from [SPARQL 1.1](http://www.w3.org/TR/sparql11-query/#propertypaths).

- many more SPARQL 1.1 ops as `builtin` tokens
- matching operators as `operator` tokens
  - added operators for [property paths](http://www.w3.org/TR/sparql11-query/#propertypaths)
- update meta to reflect documentation
  - sets mime type to [`application/sparql-query`](http://www.w3.org/TR/sparql11-query/#mediaType)
  - sets extension to `qr`
  - extra alias for SPARUL (it's the same thing)
- more content in demo showing new token types

happy to provide more documentation, or change specific token types to be more in line with other things... it would be great to get some consistency between sparql, n-triples and turtle, but this seemed like a good place to start, while the others were a little quirkier.