Publish data for certificates

Fixes theodi/shared#54

I've now got Turtle, RDF/XML and JSON being generated for certificates. Example Turtle is as follows:

	@prefix cert: <http://schema.theodi.org/certificate#> .
	@prefix dcat: <http://www.w3.org/ns/dcat#> .
	@prefix dct: <http://purl.org/dc/terms/> .
	@prefix foaf: <http://xmlns.com/foaf/0.1/> .
	@prefix jurisdiction: <https://certificates.theodi.org/jurisdictions/> .
	@prefix odrs: <http://schema.theodi.org/odrs#> .
	@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
	@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
	@prefix skos: <http://www.w3.org/2004/02/skos/core#> .
	@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

	<http://open-data-certificate.dev/datasets/590> a dcat:Dataset;
	   dct:title "Defence Infrastructure Organisation Disposals Database House of Commons Report";
	   dct:publisher [ a foaf:Organization;
	     foaf:name "Defence Infrastructure Organisation"];
	   dct:rights [ a odrs:RightsStatement;
	     odrs:contentLicence <http://reference.data.gov.uk/id/open-government-licence>;
	     odrs:dataLicence <http://reference.data.gov.uk/id/open-government-licence>];
	   cert:certificate <http://open-data-certificate.dev/datasets/590/certificates/602>;
	   foaf:homepage <http://courses.dev/open-data-in-practice> .

	<http://open-data-certificate.dev/datasets/590/certificates/602> a cert:Certificate,
	     cert:BasicCertificate;
	   rdfs:label "Open Data Certificate for Defence Infrastructure Organisation Disposals Database House of Commons Report";
	   dct:published "2013-08-02Z"^^xsd:date;
	   cert:answer [ a cert:Answer;
	     rdfs:label "Where is it described?";
	     cert:question <https://certificates.theodi.org/surveys/questions/7438>;
	     cert:response <http://courses.dev/open-data-in-practice>],
	     [ a cert:Answer;
	     rdfs:label "Who publishes this data?";
	     cert:question <https://certificates.theodi.org/surveys/questions/7442>;
	     cert:response "This data is published by Defence Infrastructure Organisation"],
	     [ a cert:Answer;
	     rdfs:label "Was all this data originally created or gathered by you?";
	     cert:question <https://certificates.theodi.org/surveys/questions/7447>;
	     cert:response "This data was originally created or generated by its curator"],
	     [ a cert:Answer;
	     rdfs:label "Under which licence can people reuse this data?";
	     cert:question <https://certificates.theodi.org/surveys/questions/7469>;
	     cert:response "This data is available under UK Open Government Licence"],
	     [ a cert:Answer;
	     rdfs:label "Under which licence can others reuse content?";
	     cert:question <https://certificates.theodi.org/surveys/questions/7477>;
	     cert:response "The content is available under UK Open Government Licence"],
	     [ a cert:Answer;
	     rdfs:label "Can individuals be identified from this data?";
	     cert:question <https://certificates.theodi.org/surveys/questions/7486>;
	     cert:response "This data contains no data about individuals"],
	     [ a cert:Answer;
	     rdfs:label "Is this data machine-readable?";
	     cert:question <https://certificates.theodi.org/surveys/questions/7579>;
	     cert:response "This data is machine-readable"],
	     [ a cert:Answer;
	     rdfs:label "Is this data in a standard open format?";
	     cert:question <https://certificates.theodi.org/surveys/questions/7581>;
	     cert:response "The format of this data is a standard open format"],
	     [ a cert:Answer;
	     rdfs:label "Does your data documentation include machine-readable data for:";
	     cert:question <https://certificates.theodi.org/surveys/questions/7613>;
	     cert:response "The documentation includes machine-readable data for title"],
	     [ a cert:Answer;
	     rdfs:label "Does your data documentation include machine-readable data for:";
	     cert:question <https://certificates.theodi.org/surveys/questions/7613>;
	     cert:response "The documentation includes machine-readable data for description"],
	     [ a cert:Answer;
	     rdfs:label "Does your data documentation include machine-readable data for:";
	     cert:question <https://certificates.theodi.org/surveys/questions/7613>;
	     cert:response "The documentation includes machine-readable data for release date"],
	     [ a cert:Answer;
	     rdfs:label "Does your data documentation include machine-readable data for:";
	     cert:question <https://certificates.theodi.org/surveys/questions/7613>;
	     cert:response "The documentation includes machine-readable data for modification date"],
	     [ a cert:Answer;
	     rdfs:label "Does your data documentation include machine-readable data for:";
	     cert:question <https://certificates.theodi.org/surveys/questions/7613>;
	     cert:response "The documentation includes machine-readable data for release frequency"],
	     [ a cert:Answer;
	     rdfs:label "Does your data documentation include machine-readable data for:";
	     cert:question <https://certificates.theodi.org/surveys/questions/7613>;
	     cert:response "The documentation includes machine-readable data for publisher"],
	     [ a cert:Answer;
	     rdfs:label "Does your data documentation include machine-readable data for:";
	     cert:question <https://certificates.theodi.org/surveys/questions/7613>;
	     cert:response "The documentation includes machine-readable data for temporal coverage"],
	     [ a cert:Answer;
	     rdfs:label "Does your data documentation include machine-readable data for:";
	     cert:question <https://certificates.theodi.org/surveys/questions/7613>;
	     cert:response "The documentation includes machine-readable data for keyword(s) or tag(s)"],
	     [ a cert:Answer;
	     rdfs:label "Does your data documentation include machine-readable data for:";
	     cert:question <https://certificates.theodi.org/surveys/questions/7613>;
	     cert:response "The documentation includes machine-readable data for distribution(s)"],
	     [ a cert:Answer;
	     rdfs:label "Who should people email with questions about this data?";
	     cert:question <https://certificates.theodi.org/surveys/questions/7642>;
	     cert:response "Send questions about this data to DIO SEC-Groupmailbox@mod.uk"];
	   cert:badge <http://open-data-certificate.dev/datasets/590/certificates/602/badge.png>;
	   cert:embeddable <http://open-data-certificate.dev/datasets/590/certificates/602/badge.js>;
	   cert:jurisdiction jurisdiction:gb .

	<https://certificates.theodi.org/surveys/categories/> a skos:ConceptScheme;
	   dct:title "Categories of questions in Open Data Certificates" .

	<https://certificates.theodi.org/surveys/questions/7438> a cert:Question;
	   rdfs:label "Where is it described?";
	   dct:subject <https://certificates.theodi.org/surveys/categories/general> .

	<https://certificates.theodi.org/surveys/questions/7442> a cert:Question;
	   rdfs:label "Who publishes this data?";
	   dct:subject <https://certificates.theodi.org/surveys/categories/general> .

	<https://certificates.theodi.org/surveys/questions/7447> a cert:Question;
	   rdfs:label "Was all this data originally created or gathered by you?";
	   dct:subject <https://certificates.theodi.org/surveys/categories/general> .

	<https://certificates.theodi.org/surveys/questions/7469> a cert:Question;
	   rdfs:label "Under which licence can people reuse this data?";
	   dct:subject <https://certificates.theodi.org/surveys/categories/general> .

	<https://certificates.theodi.org/surveys/questions/7477> a cert:Question;
	   rdfs:label "Under which licence can others reuse content?";
	   dct:subject <https://certificates.theodi.org/surveys/categories/general> .

	<https://certificates.theodi.org/surveys/questions/7486> a cert:Question;
	   rdfs:label "Can individuals be identified from this data?";
	   dct:subject <https://certificates.theodi.org/surveys/categories/general> .

	<https://certificates.theodi.org/surveys/questions/7579> a cert:Question;
	   rdfs:label "Is this data machine-readable?";
	   dct:subject <https://certificates.theodi.org/surveys/categories/general> .

	<https://certificates.theodi.org/surveys/questions/7581> a cert:Question;
	   rdfs:label "Is this data in a standard open format?";
	   dct:subject <https://certificates.theodi.org/surveys/categories/general> .

	<https://certificates.theodi.org/surveys/questions/7642> a cert:Question;
	   rdfs:label "Who should people email with questions about this data?";
	   dct:subject <https://certificates.theodi.org/surveys/categories/general> .

	<https://certificates.theodi.org/surveys/questions/7613> a cert:Question;
	   rdfs:label "Does your data documentation include machine-readable data for:";
	   dct:subject <https://certificates.theodi.org/surveys/categories/general> .

	<https://certificates.theodi.org/surveys/categories/general> a skos:Concept;
	   skos:inScheme <https://certificates.theodi.org/surveys/categories/>;
	   skos:prefLabel "General Information" .

And here's the JSON:

	{
	  "certificate": {
	    "title": "Defence Infrastructure Organisation Disposals Database House of Commons Report",
	    "jurisdiction": {
	      "label": "GB",
	      "uri": "https://certificates.theodi.org/jurisdictions/gb"
	    },
	    "level": {
	      "label": "Basic",
	      "uri": "http://schema.theodi.org/certificate#BasicCertificate"
	    },
	    "created_at": "2013-08-02T10:40:44Z",
	    "responses": [
	      {
	        "question": {
	          "text": "Where is it described?",
	          "uri": "https://certificates.theodi.org/surveys/questions/7438"
	        },
	        "answer": {
	          "text": "This data is described at http://courses.dev/open-data-in-practice"
	        }
	      },
	      {
	        "question": {
	          "text": "Who publishes this data?",
	          "uri": "https://certificates.theodi.org/surveys/questions/7442"
	        },
	        "answer": {
	          "text": "This data is published by Defence Infrastructure Organisation"
	        }
	      },
	      {
	        "question": {
	          "text": "Was <em>all</em> this data originally created or gathered by you?",
	          "uri": "https://certificates.theodi.org/surveys/questions/7447"
	        },
	        "answer": {
	          "text": "This data was originally created or generated by its curator"
	        }
	      },
	      {
	        "question": {
	          "text": "Under which licence can people reuse this data?",
	          "uri": "https://certificates.theodi.org/surveys/questions/7469"
	        },
	        "answer": {
	          "text": "This data is available under UK Open Government Licence"
	        }
	      },
	      {
	        "question": {
	          "text": "Under which licence can others reuse content?",
	          "uri": "https://certificates.theodi.org/surveys/questions/7477"
	        },
	        "answer": {
	          "text": "The content is available under UK Open Government Licence"
	        }
	      },
	      {
	        "question": {
	          "text": "Can individuals be identified from this data?",
	          "uri": "https://certificates.theodi.org/surveys/questions/7486"
	        },
	        "answer": {
	          "text": "This data contains no data about individuals"
	        }
	      },
	      {
	        "question": {
	          "text": "Is this data machine-readable?",
	          "uri": "https://certificates.theodi.org/surveys/questions/7579"
	        },
	        "answer": {
	          "text": "This data is machine-readable"
	        }
	      },
	      {
	        "question": {
	          "text": "Is this data in a standard open format?",
	          "uri": "https://certificates.theodi.org/surveys/questions/7581"
	        },
	        "answer": {
	          "text": "The format of this data is a standard open format"
	        }
	      },
	      {
	        "question": {
	          "text": "Does your data documentation include machine-readable data for:",
	          "uri": "https://certificates.theodi.org/surveys/questions/7613"
	        },
	        "answer": {
	          "text": "The documentation includes machine-readable data for title"
	        }
	      },
	      {
	        "question": {
	          "text": "Does your data documentation include machine-readable data for:",
	          "uri": "https://certificates.theodi.org/surveys/questions/7613"
	        },
	        "answer": {
	          "text": "The documentation includes machine-readable data for description"
	        }
	      },
	      {
	        "question": {
	          "text": "Does your data documentation include machine-readable data for:",
	          "uri": "https://certificates.theodi.org/surveys/questions/7613"
	        },
	        "answer": {
	          "text": "The documentation includes machine-readable data for release date"
	        }
	      },
	      {
	        "question": {
	          "text": "Does your data documentation include machine-readable data for:",
	          "uri": "https://certificates.theodi.org/surveys/questions/7613"
	        },
	        "answer": {
	          "text": "The documentation includes machine-readable data for modification date"
	        }
	      },
	      {
	        "question": {
	          "text": "Does your data documentation include machine-readable data for:",
	          "uri": "https://certificates.theodi.org/surveys/questions/7613"
	        },
	        "answer": {
	          "text": "The documentation includes machine-readable data for release frequency"
	        }
	      },
	      {
	        "question": {
	          "text": "Does your data documentation include machine-readable data for:",
	          "uri": "https://certificates.theodi.org/surveys/questions/7613"
	        },
	        "answer": {
	          "text": "The documentation includes machine-readable data for publisher"
	        }
	      },
	      {
	        "question": {
	          "text": "Does your data documentation include machine-readable data for:",
	          "uri": "https://certificates.theodi.org/surveys/questions/7613"
	        },
	        "answer": {
	          "text": "The documentation includes machine-readable data for temporal coverage"
	        }
	      },
	      {
	        "question": {
	          "text": "Does your data documentation include machine-readable data for:",
	          "uri": "https://certificates.theodi.org/surveys/questions/7613"
	        },
	        "answer": {
	          "text": "The documentation includes machine-readable data for keyword(s) or tag(s)"
	        }
	      },
	      {
	        "question": {
	          "text": "Does your data documentation include machine-readable data for:",
	          "uri": "https://certificates.theodi.org/surveys/questions/7613"
	        },
	        "answer": {
	          "text": "The documentation includes machine-readable data for distribution(s)"
	        }
	      },
	      {
	        "question": {
	          "text": "Who should people email with questions about this data?",
	          "uri": "https://certificates.theodi.org/surveys/questions/7642"
	        },
	        "answer": {
	          "text": "Send questions about this data to DIO SEC-Groupmailbox@mod.uk"
	        }
	      }
	    ]
	  }
	}

Thoughts welcome, on code and data!