fixed another bug in gradBiasBatch, now should be bug free
fixed another bug in gradBiasBatch, now should be bug free

colesbury/cunn,lukasc-ch/cunn,hughperkins/cunn,Saulzar/cunn,clementfarabet/cunn,Aysegul/cunn,apaszke/cunn,andreaskoepf/cunn,jhjin/cunn,ml-lab/cunn,albanD/cunn,davidBelanger/cunn,jonathantompson/cunn,soumith/cunnsparse,colesbury/cunn,apaszke/cunn,rotmanmi/cunn,rotmanmi/cunn,andreaskoepf/cunn,fmassa/cunn,apaszke/cunn,ominux/cunn,szagoruyko/cunn,clementfarabet/cunn,jonathantompson/cunn,danielsig727/cunn,jhjin/cunn,szagoruyko/cunn,colesbury/cunn,lukasc-ch/cunn,davidBelanger/cunn