Test the SBOL-Visual ontology

[goksel]

Test the SBOL-visual ontology with reference to the README file in the Glyphs directory.
The ontology is available as an RDF file (Ontology/v2/sbol-vo.rdf) and can be viewed using Protege (https://protege.stanford.edu/products.php). The ontology is also available as a human readable HTML file which can be found at Ontology/v2/sbol-vo.html.

[goksel]

@jakebeal I suggest closing this issue since we are able to produce the ontology file and we can review it using Protege.

[jakebeal]

The goal of this issue is to make sure that the ontology can be generated and the most recent version of it be accessed via the webservice --- basically, all the things described in the ontology directory README.

Hand-inspection will always be needed to some degree to ensure semantic correctness, but we should be able to automatically check that the pipeline from READMEs to ontology to webservice isn't being broken by a chance. That will mean that ontology updates can be pre-staged just like we do specification changes, rather than having to be done manually.

This issue becomes critical in enabling #116