put out mapping as RDF

[VladimirAlexiev]

https://twitter.com/ewg118/status/739446119701319680
@ewg118 Now to get PleiadesProject URIs back into the Getty TGN? cc @azaroth42

1993 matches in https://github.com/ryanfb/pleiades-tgn/blob/master/pleiades-tgn.csv

1. I think we first need some (evidence of) manual verification. 1993 matches, I think it's enough to check 50?
2. Then we can either include it in http://vocab.getty.edu/dataset/tgn/ (see http://vocab.getty.edu/doc/#Alignment), or in some Pleiades download.
3. Pleaiades places are also considered skos:Concept; in TGN we have dual nodes tgn:1007100 a skos:Concept and tgn:1007100-place a schema:Place, so the appropriate statement is:
   <http://pleiades.stoa.org/places/462425> skos:exactMatch <http://vocab.getty.edu/tgn/1007100>
4. Should also be added to http://pleiades.stoa.org/places/462425 and http://pleiades.stoa.org/places/462425/turtle.

[paregorios]

@VladimirAlexiev issues specifically for Pleiades and its RDF would be most welcome in this tracker: https://github.com/isawnyu/pleiades-gazetteer/issues !

[ryanfb]

This follows along some work @rsimon did following on from this thread: https://twitter.com/ryanfb/status/718446369728512000

I've pulled/merged his initial RDF conversion script in #3, and will take a look from there.

[VladimirAlexiev]

@paregorios: added isawnyu/pleiades-gazetteer#153