Created NeuronNetwork class

I have coded the default constructor and Serializable, Cloneable,
Iterable<NeuronLayer>, Collection<NeuronLayer>, List<NeuronLayer>,
RandomAccess interfaces
Added an small coment to serializable attribute
Added spreadOut and getOutput methods

SpreadOut will spread all outputs from input layer to output layer.

getOutput will return an ArrayList<Number> with all outputs of the
specified layer. If a layer is not specified it will return the outputs
of last layer.
Added method to initialize class from topology vector
Added constructor from topology vector
initializeFromTopologyVector will spreadOut too
Added feedNeurons and calculateOutputError methods
Added coefficients attribute
Added a lot of methods
Corrected clearInputs to clear _coefficients too
Added cloneNet method
Added clone override
Added clone method
Added restoreNetFrom method
Added toString method
Added updateDeltas method
Added updateChanges and corrected spreadOut method

spreadOut method now will not destroy coefficients vector when it
founds that new values length and old values length are equal
Added adjust weights method
Added lastInputChange attributes
Updated adjustWeights to use last input change information