further refactoring

network-test.ipynb

network-test.py

nn/__init__.py

nn/layer/__init__.py

nn/layer/activation.py

nn/layer/batchNorm.py

nn/layer/convolution1D.py

nn/layer/convolution2D.py

nn/layer/graph.py

nn/layer/hopfield.py

nn/layer/layer.py

nn/layer/linear.py

nn/layer/lstm.py

nn/layer/norm.py

nn/layer/pooling1d.py

nn/layer/pooling2d.py

nn/layer/regularization.py

nn/layer/rnn.py

nn/layer/transposed.py

nn/layer/weights.py