Fix SpatialAveragePooling.
Fix SpatialAveragePooling.

Use atomic version of subgradinput in the non-batch case if kH != dH or
kW != dW.

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