Implements Multiclass hinge loss

Implements multiclass hinge loss. Fixes #3451 
I am using the formula given in section 2(Definitions) of this paper
http://www.ttic.edu/sigml/symposium2011/papers/Moore+DeNero_Regularization.pdf

I thought we should multiply label with functional margins. Thus I multiplied -1 to all other pred_decisions.  Please correct me if I am wrong