Revise coredataextractor feature code labelling

[kintopp]

abosse$ python get_core_data.py placehierarchy 3090048
3090048   # Opole (Populated place (ppla))
798544    # Poland (Country)
3337495   # Opole Voivodeship (Region (adm1))
7532413   # Opole (City   (adm3})
7530818   # Opole (County (adm2))

Later, we'll want to revise the labels accompanying the feature codes (PPLA etc.) provided by GeoNames. For example, ADM3 in this context means 'administrative seat of the county of Opole' rather than 'city' of Opele as a 'populated place', which is captured by the PPL hierarchy.

See http://www.geonames.org/export/codes.html