Add cudnn mode selection in softmax
Add cudnn mode selection in softmax

keisuke-umezawa/chainer,jnishi/chainer,wkentaro/chainer,ronekko/chainer,jnishi/chainer,keisuke-umezawa/chainer,chainer/chainer,tkerola/chainer,jnishi/chainer,wkentaro/chainer,hvy/chainer,okuta/chainer,niboshi/chainer,niboshi/chainer,hvy/chainer,chainer/chainer,wkentaro/chainer,wkentaro/chainer,jnishi/chainer,ktnyt/chainer,anaruse/chainer,okuta/chainer,niboshi/chainer,ktnyt/chainer,okuta/chainer,aonotas/chainer,ktnyt/chainer,niboshi/chainer,keisuke-umezawa/chainer,okuta/chainer,pfnet/chainer,rezoo/chainer,chainer/chainer,ktnyt/chainer,hvy/chainer,chainer/chainer,hvy/chainer,keisuke-umezawa/chainer