[RefData][ORI] Added Geonames ID for NBU/Glenview, IL, USA and NBV/Canabrava, MG, BR.
[RefData][Geonames] Updated the header of the generated file, so as match the ORI ones.
[RefData][ORI] Added Geonames ID for JUH/Chizhou Jiuhuashan, China.
[RefData][Tools] Simplified the extraction from Geonames.
* Three files are generated:
** por_all_iata_YYYYMMDD.csv: POR having got a IATA code,
   be them travel-related or city-related
** por_all_icao_only_YYYYMMDD.csv: POR having a ICAO code
   and no IATA code
** por_all_nocode_20131111.csv: POR having neither
   a IATA code nor a ICAO code
* ZZZZ and NULL are no longer used. The corresponding fields
  (e.g., ICAO code) are not simply empty. That behaviour is more
  consistent, as all the other fields (e.g., FAA code, Wiki link)
  were empty.