Compare rdf libraries for query efficiency

[mpsonntag]

Use the Example Queries from #142 and #148 on a graph combining all example files with different rdf libraries. Provide a graph to compare the efficiency of the different libraries.

[mpsonntag]

In addition to the two queries mentioned above, use an additional very simple query as discussed before:

q2 = prepareQuery("""SELECT ?s
           WHERE {
              ?d rdf:type odml:Document .
              ?d odml:hasSection ?s .
              ?s odml:hasType "Recording"
           }""", initNs={"odml": Namespace("https://g-node.org/projects/odml-rdf#"),
                         "rdf": RDF})

[mpsonntag]

We are sticking withrdflib. Closing issue.