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
Modification based on Pull Request comments.
Final changes to RandomForest example
Adding explanatory comments in RandomForest example
changing learner's number of features to 4 (better classifier performance)
GROUPing by "group_id and id " before dedup0 and dedup1
Merge pull request #181 from DonVitorio/AreaUnderROCCurve

Area Under the ROC Curve