[Fix] BackPropagation: removed unnecessary neural net copy when
      computing outputs on validation set.
[Fix] Statistics: removed unnecessary neural net copy when computing
      outputs on test set.
[Fix] EarlyStop: isGeneralizationLossMet().
      use 'validation output vectors' instead of 'training output
      vectors'.
[Fix] SupervisedLearning: getEarlyStop(), getMaxEpochsStop().
      added 'break' statement to cut iteration.