add superseded languoids to exports

[xrotwang]

to ensure referential integrity. Alternatively remove all languoids referencing superseded ones.

[xrotwang]

information about status and active-flag is encoded as skos notes:

<rdf:RDF xmlns:foaf="http://xmlns.com/foaf/0.1/"
  xmlns:owl="http://www.w3.org/2002/07/owl#"
  xmlns:gold="http://purl.org/linguistics/gold/"
  xmlns:void="http://rdfs.org/ns/void#"
  xmlns:dc="http://purl.org/dc/elements/1.1/"
  xmlns:isbd="http://iflastandards.info/ns/isbd/elements/"
  xmlns:frbr="http://purl.org/vocab/frbr/core#"
  xmlns:skos="http://www.w3.org/2004/02/skos/core#"
  xmlns:vcard="http://www.w3.org/2001/vcard-rdf/3.0#"
  xmlns:lexvo="http://lexvo.org/ontology"
  xmlns:bibo="http://purl.org/ontology/bibo/"
  xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
  xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#"
  xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  xmlns:dcterms="http://purl.org/dc/terms/">
    <rdf:Description rdf:about="http://localhost:6543/resource/languoid/id/elli1237">
        <void:inDataset rdf:resource="http://localhost:6543/"/>
        <rdfs:label xml:lang="en">Ellicean</rdfs:label>
        <skos:prefLabel xml:lang="en">Ellicean</skos:prefLabel>
        <dcterms:title xml:lang="en">Ellicean</dcterms:title>
        <rdf:type rdf:resource="http://purl.org/dc/terms/LinguisticSystem"/>
        <skos:changeNote>obsolete</skos:changeNote>
        <rdf:type rdf:resource="http://purl.org/linguistics/gold/LanguageFamily"/>
        <skos:editorialNote>established</skos:editorialNote>
        <dcterms:isReplacedBy rdf:resource="http://localhost:6543/resource/languoid/id/elli1239"/>
    </rdf:Description>
</rdf:RDF>