[Fix] learning/stop/EarlyStop: isMet(). Java was doing Lazy Evaluation
      in the conditional checking at the return statement, making
      isMinTrainingProgressMet() not to be invoked. We want to invoke it
      even if it is not satisfied, because we want to store the values
      for later analization.
[Fix] test/Statistics refactored. Move storing of etrs, evas, gls, pks
      to SupervisedLearning to avoid redundancy and for better grouping
      of properties.