CNNNetwork can now use any columns for focused CNNs

decoder/src/Decoder.cpp

reading_machine/src/Classifier.cpp

torch_modules/include/CNN.hpp

torch_modules/include/CNNNetwork.hpp

torch_modules/include/NeuralNetwork.hpp

torch_modules/src/CNN.cpp

torch_modules/src/CNNNetwork.cpp

torch_modules/src/NeuralNetwork.cpp