Changes
- Added activation functions (ELU/Hyperbolic tangent/Identity/ReLU/SELU/Sigmoid/Softmax/SoftPlus/Softsign).
- Added layers (Batch normalization/Convolutional/Dropout/Fully connected/Max pooling).
- Added loss functions (Cross-entropy/Mean squared error).
- Added optimizers (AdaDelta/AdaGrad/Adam/Momentum/Nesterov/RMSprop/SGD).