[x] Pinball Loss (or Quantile Loss)
[x] Loss Balancer (a class for tackling the classification problem on imbalanced dataset)
[x] MultiTaskLoss
[x] PDFLoss
[x] MacroDoubleSoftF1Loss
[x] Elastic Loss Term (= L1 reguralization + L2 reguralization like sklearn's ElasticNet)
[ ] Affinity Loss <- Please Fix me.