kmeans_visualizer.show_clusters ignore `display=False`

[yasirroni]

Using both display=False and display=True results in same thing.

It's just ugly that kmeans_visualizer.show_clusters display image two times.

I would prefer user to be able to use

visualizer.append_clusters(clusters, input_data);
# visualizer.__draw_centers(visualizer, offset, visualizer, centers, initial_centers)
# visualizer.__draw_rays(visualizer, offset, visualizer, sample, clusters, centers)
visualizer.show();

Not the figure.