Update SoftMax to work in spatial mode
Update SoftMax to work in spatial mode

This updates SoftMax to work in spatial mode thus it accepts 1D/2D/3D/4D
tensor as input.

andreaskoepf/cunn,clementfarabet/cunn,rotmanmi/cunn,apaszke/cunn,colesbury/cunn,szagoruyko/cunn,jhjin/cunn,clementfarabet/cunn,colesbury/cunn,apaszke/cunn,rotmanmi/cunn,colesbury/cunn,szagoruyko/cunn,lukasc-ch/cunn,jonathantompson/cunn,andreaskoepf/cunn,jhjin/cunn,jonathantompson/cunn,danielsig727/cunn,lukasc-ch/cunn,apaszke/cunn