Implement high level interface for MLPACK comparison

[mircodemarchi]

We chose MLPACK as a reference framework for a preliminary comparison of the level of efficiency and accuracy of the implemented models.

[mircodemarchi]

Implementation of two high level interface:

• Feedforward Neural Network (FNN)
• Recurrent Neural Network (RNN)

[mircodemarchi]

Implementation of FNN high level interface done in f2031c8