function readLatLngGeoJson(cAddress) {
    return [readSingleCoord(cAddress + SZ_DBL), readSingleCoord(cAddress)];
}
Read a LatLng from C and return a GeoJSON-style [lng, lat] pair.
@private
@param  {number} cAddress    Pointer to C struct
@return {CoordPair}          [lng, lat] pair