Add a pseudo HTTP parameter for the RDF document

[jmvanel]

There could be a "pseudo HTTP parameter" url= specifying the RDF document, appended to the path to node-arc-d3 , like this:
file:///home/jmv/src/node-arc-d3/index.html?url=http://bshambaugh.org/foaf.rdf#me

This is how RDFViewer ( another nice RDF diagramming tool ) works :
http://semantic-forms.cc:9112/assets/rdfviewer/rdfviewer.html?url=http%3A%2F%2Fbshambaugh.org%2Ffoaf.rdf%23me

Implementation

just a few lines of JS code in
http://semantic-forms.cc:9112/assets/rdfviewer/rdfviewer.html
copied from
https://github.com/jimmccusker/rdfviewer/blob/master/index.html