Neural network for MNIST dataset.

• mnist
  Training network by MNIST dataset.
  Any data assort.

• mnist_and_soccerball
  Training network by MNIST dataset and soccer ball image.
  Digit and soccer ball image assort.

• mnist_by_cnn
  Training network by MNIST dataset.
  Using Convolutional neural network.

• mnist_with_backpropagation
  Training network by MNIST dataset.
  Using backpropagation and stochastic gradient discent.