Merge branch 'regression-846' into develop

Modules/Applications/AppClassification/app/CMakeLists.txt

...plications/AppClassification/app/otbPredictRegression.cxx

...ations/AppClassification/app/otbTrainImagesClassifier.cxx

...ications/AppClassification/app/otbTrainImagesClassifier.h

...Applications/AppClassification/app/otbTrainRegression.cxx

...ns/AppClassification/include/otbLearningApplicationBase.h

.../AppClassification/include/otbLearningApplicationBase.txx

.../Applications/AppClassification/include/otbTrainBoost.txx

...ations/AppClassification/include/otbTrainDecisionTree.txx

...AppClassification/include/otbTrainGradientBoostedTree.txx

...es/Applications/AppClassification/include/otbTrainKNN.txx

...Applications/AppClassification/include/otbTrainLibSVM.txx

...tions/AppClassification/include/otbTrainNeuralNetwork.txx

...cations/AppClassification/include/otbTrainNormalBayes.txx

...tions/AppClassification/include/otbTrainRandomForests.txx

...es/Applications/AppClassification/include/otbTrainSVM.txx

Modules/Applications/AppClassification/test/CMakeLists.txt

...earning/Supervised/include/otbBoostMachineLearningModel.h

...rning/Supervised/include/otbBoostMachineLearningModel.txx

.../Supervised/include/otbDecisionTreeMachineLearningModel.h