code: boolean containsExclusive(Envelope2D other) {
  		// Note: This will return False, if either envelope is empty, thus no
  		// need to call is_empty().
  		return other.xmin > xmin && other.xmax < xmax && other.ymin > ymin
  				&& other.ymax < ymax;
  	}
docs: Returns True if the envelope contains the other envelope (boundary
  exclusive).
  @param other The other envelope
  @return True if this contains the other, boundary exclusive.