Weka Regression from XRFF file.

The here shown workflow splits the given data into a training set and a test set. Afterwards a machine learning model is created by the Weka Regression worker which is evaluated by the Evaluate Regression Results as PDF worker. The resulting sets are stored as XRFF files in the folder determined by the OUT TRAIN XRFF and OUT TEST XRFF input ports. The calcualted machine learning models and the evaluation results are saved in the folder of OUT MODEL input port