Defined basic interface with MultilayerPerceptron.

Also has been defined the public constructor.
Added Serial version to Serizable interface
Interfaces implemented
Added commenters to the Default constructor
Added a new constructor with comments.

The new constructor initialize the object with a ArrayList<NeuronLayer>
argument
Added the method getLayers.

It returns all the layers into the MultilayerPerceptron in a
ArrayList<NeuralLayer>
Added default copy constructor
Added input matrix
Removed matrix's layers input
Created a basic test for MultilayerPerceptron
Added default constructor to the tests
Implemented test to check default constructor
Implemented test to check constructor with ArrayList of NeuronLayer
Implemented test to check default copy constructor
Implemented test to check getLayers method
Update getLayers test
Updated test to check a MultilayerPerceptron copy
Created equals method
Added overhead to get method.

Now get method can return a neuron if you specify a subindex.
Created a test to check new get method