Issue Description:

I retrieve the content of my corese dataset with a CONSTRUCT { GRAPH ?g { ?s ?p ?o } } WHERE { GRAPH ?g { ?s ?p ?o } } query, with "accept": "application/trig" as header. When constructing my KG from the content of some external sources, the TriG file returned by Corese is sometimes not valid. The brackets < and > are missing from some properties.

Bug Details:

There are no error messages on the corese side, but any parser receiving the data fails to parse the TriG content because of that.

Steps to Reproduce:

1. Create data that generates the bug:

INSERT DATA {
  <http://bio2rdf.org/lsr:aclame> <http://bio2rdf.org/lsr_vocabulary:x-miriam> <http://bio2rdf.org/miriam:00000063>
}

2. Retrieve the data in TriG format, with "accept": "application/trig" as header

CONSTRUCT { ?s ?p ?o } WHERE { ?s ?p ?o }

3. The result of the CONSTRUCT query is:

@prefix ns1: <http://bio2rdf.org/> .


<http://bio2rdf.org/lsr:aclame> http://bio2rdf.org/lsr_vocabulary:x-miriam <http://bio2rdf.org/miriam:00000063> .

Expected Behavior:
The content of the result of the CONSTRUCT should be equivalent to the triple created.

Note to Developers:
My hypothesis is that the presence of a second ":" in the property URI messes up in some way the TriG serializer.
This could also impact ticket Wimmics/corese-ark#19 , and using the CONSTRUCT as I do now is already my only solution to retrieve the content of my Corese server.

Details
Tested on corese-server-4.4.1.jar