Extra information for Pleiades place RDF

[sgillies]

To add to the RDF document for a place:

• [x] its locations, using pleiades:hasLocation
• [x] its names, using pleiades:hasName
• [x] dc:creator, dc:contributor
• [x] citations, using cito terms
• [x] temporal attestations, using pleiades:duration
• [x] location geometry using osgeo:asGeoJSON (see http://atlantides.org/capgrids/1.ttl)
• [x] name pleiades:nameRomanized
• [x] name pleiades:nameAttested
• [x] initial provenance http://www.w3.org/TR/prov-o/#wasDerivedFrom
• [x] SKOS-ify time periods, adding their date ranges
• [x] Document