code: public Envelope TileLatLonBounds( int tx, int ty, int zoom ) {
          double[] wsenBounds = TileBounds(tx, ty, zoom);
          double[] sw = MetersToLatLon(wsenBounds[0], wsenBounds[1]);
          double[] ne = MetersToLatLon(wsenBounds[2], wsenBounds[3]);
          return new Envelope(sw[1], ne[1], sw[0], ne[0]);
      }
docs: Returns bounds of the given tile in latitude/longitude using WGS84 datum
  
  return the array of [w, s, e, n]