Computation times

00:38.235 total execution time for 2 files from auto_examples/model_selection:

Example	Time	Mem (MB)
Plotting Validation Curves (plot_validation_curve.py)	00:20.335	290.9
Distribute hard-to-classify datapoints over CV folds (plot_instance_hardness_cv.py)	00:17.899	285.6