Fix bug when batch_size > dataset size
Fix bug when batch_size > dataset size

If batch size is greater than the total size of the data set, no data will be yielded from _iterate_data.  Consequently, no training will happen and you will get a ZeroDivision error for "loss / count" in _batch_impl.  Also, it only generates batches of the exact size - any remaining data at the end is not trained on.
aigamedev/scikit-neuralnetwork