[ACTION-501] Federated query review

Here's my (delayed) review of the federated query document - there are mostly editorial comments - minor ones except the first one that I think should be addressed before the publishing.
This completes ACTION-501

Best,

Alex.

* TOC
- Appendix C1 to be removed

* 2 (intro):
- You use "SPARQL protocol service" but in the rest of the document, "SPARQL endpoint". Is that the same thing ? If so, that should should be replaced, if not "protocol service" should be explained. Similarly, in 2.2 you use *service* ("Data in the default graph at service: http://people.example.org/sparql") and in 2.3 *endpoint* (Data in <http://people.example.org/sparql> endpoint). This is the only major concern I have with the current spec but I think that should be fixed.

* 2.1
- "and we want to combine it with my local FOAF file". I'd rather use neutral pronouns. "one wants to combine with a local FOAF file". That's a general remark to avoid the use of "we" that sounds too tutorial-ish too me.

* 2.2
- "Data in <http://people.example.org/sparql> endpoint". Endpoint URL should be in <code>

* 2.4.
-  for all foaf:Persons. Put the "s" outside the <code>, or better, replace by "instances of foaf:Person"

* 4
- "DOAP vocabulary" . Add an hyperlink of reference.
- "  void:sparqlEndpoint ?service " I think there's a . missing here

--
Dr. Alexandre Passant, 
Social Software Unit Leader
Digital Enterprise Research Institute, 
National University of Ireland, Galway