Generate SPARQL queries without ";" or ","

[tfrancart]

Because Sparnatural does text-based search/replace post-processing on the generated SPARQL string, I would need to pass an option to the SPARQL generator to tell it to always use an :s :p :o . pattern for triples inside bgp, and never use the ; or , separators to separate triples with the same subject, or the same subject and predicate.

[RubenVerborgh]

We can accept a PR for this, would you be willing to write the code?

[rubensworks]

It might be interesting to do such operations using SPARQL algebra instead. (as that's what algebra is meant for)

[tfrancart]

See also #71