+ Reformat ClassificationMetric, RegressionMetric, and ClusteringMetric
+ Fix bugs in metrics:
+ ROC-AUC score
+ F2 score, FBeta score
+ Hamming Score, Accuracy Score
+ Add metrics to ClassificationMetric:
+ Brier Score Loss (BSL)
+ Kullback-Leibler Divergence Loss (KLDL)
+ Cross-Entropy Loss (CEL)
+ Hinge Loss (HL)
+ Update docs, examples
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