Area Under the ROC Curve
- Separate ensemble functions from Trees.ecl and create Ensemble.ecl
- Modify Classify.ecl to use Ensemble.ecl (Random Forest)
- Calculate Class Probability Distribution in Random Forest
- Calculate Area Under ROC Curve given Class Probaiblity Distribution, class of interest,
  and actual class values.
- Modify test/explanatory/randomforest, add area under ROC performance to results