RDF output fix

[kellrott]

Making sure the RDF converter code outputs with label data.

[adamstruck]

I went through and loaded pathway commons into the viewer. I am not sure what this graph should look like, but I was surprised to see the Biopax:Gene vertex (and many others) disconnected from the rest of the graph.

[kellrott]

bioPax:Gene should connect to biopax:RelationshipXref

Example connection:

biopax:Gene

{"gid":"pc:Gene_refseq_XP_016871661_identity_1524631492674","label":"biopax:Gene","data":{"biopax:comment":"psi-mi participant","biopax:displayName":"HPS1","biopax:name":"RP11-439D8.1"}}

Edge outward:

{"label":"biopax:xref","from":"pc:Gene_refseq_XP_016871661_identity_1524631492674","to":"pc:RelationshipXref_refseq_NM_001322485"}

Destination:

{"gid":"pc:RelationshipXref_refseq_NM_001322485","label":"biopax:RelationshipXref","data":{"biopax:db":"refseq","biopax:id":"NM_001322485"}}