Add a working example of StratifiedKFold cross-validation on MNIST with Keras.
Add a working example of StratifiedKFold cross-validation on MNIST with Keras.

Compute the mean/std of the loss and accuracy metrics over the folds.

bzamecnik/ml-playground,bzamecnik/ml,bzamecnik/ml,bzamecnik/ml-playground,bzamecnik/ml