Update bf_work.py - added SPARQL for bf:genreForm

[kallimathios]

added SPARQL for bf:genreForm to line 83, under subject definition

[jermnelson]

The genre SPARQL query template should be it's own variable instead being a part of the subject variable otherwise it is an invalid SPARQL query, i.e.

genre = """PREFIX bf: <http://id.loc.gov/ontologies/bibframe/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>

SELECT ?genre
WHERE {{
    <{bf_work}> a bf:Work .
    <{bf_work}> bf:genreForm ?genre_node .
    OPTIONAL {{
        ?genre_node rdfs:label ?genre .
    }}
}}"""

You'll then need to add the new genre template to the following places:

• build.py's transformers dict, something like genre: _subjects,
• map.py's BF_TO_FOLIO_MAP