Neural network

Closes #7

See merge request !4

# Conflicts:
#   java-wowa-training.iml
#   pom.xml

New HyperParameters class + update structure of the project : some methods are now in TrainingDataset class

Change structure of NeuralNetwork. Same structure as Trainer class: constructor + run method to run the learning

Add run methods to use a Neural Network with the same structure as wowa-training. The goal is to use the same dataset in each learning to compare the performance