Changed the way context indexes are handled by NeuralNetwok

common/include/util.hpp

common/src/util.cpp

reading_machine/include/Config.hpp

reading_machine/src/Classifier.cpp

reading_machine/src/Config.cpp

torch_modules/include/CNNNetwork.hpp

torch_modules/include/ConcatWordsNetwork.hpp

torch_modules/include/LSTMNetwork.hpp

torch_modules/include/NeuralNetwork.hpp

torch_modules/include/OneWordNetwork.hpp

torch_modules/include/RLTNetwork.hpp

torch_modules/src/CNNNetwork.cpp

torch_modules/src/ConcatWordsNetwork.cpp

torch_modules/src/LSTMNetwork.cpp

torch_modules/src/NeuralNetwork.cpp

torch_modules/src/OneWordNetwork.cpp

torch_modules/src/RLTNetwork.cpp