message: replace non-existent artwork slug
diff: - (ARCellData *)jumpToArtwork
  {
  return [self tappableCellDataWithTitle:@"Artwork" selection:^{
  - id viewController = [[ARArtworkComponentViewController alloc] initWithArtworkID:@"ramon-vilanova-painting"];
  + id viewController = [[ARArtworkComponentViewController alloc] initWithArtworkID:@"alexander-calder-the-hand-of-fatima-1"];
  [self.navigationController pushViewController:viewController animated:YES];
  }];
  }
  