Update MNIST example for CuPy
Update MNIST example for CuPy

kashif/chainer,wkentaro/chainer,ktnyt/chainer,chainer/chainer,sinhrks/chainer,keisuke-umezawa/chainer,okuta/chainer,cupy/cupy,ktnyt/chainer,jnishi/chainer,truongdq/chainer,keisuke-umezawa/chainer,ytoyama/yans_chainer_hackathon,cemoody/chainer,laysakura/chainer,wkentaro/chainer,tigerneil/chainer,wkentaro/chainer,ktnyt/chainer,1986ks/chainer,masia02/chainer,okuta/chainer,truongdq/chainer,jnishi/chainer,ikasumi/chainer,ktnyt/chainer,anaruse/chainer,hvy/chainer,AlpacaDB/chainer,hidenori-t/chainer,jnishi/chainer,pfnet/chainer,jnishi/chainer,niboshi/chainer,wkentaro/chainer,hvy/chainer,hvy/chainer,rezoo/chainer,muupan/chainer,niboshi/chainer,keisuke-umezawa/chainer,kikusu/chainer,aonotas/chainer,chainer/chainer,benob/chainer,kikusu/chainer,cupy/cupy,ronekko/chainer,tkerola/chainer,AlpacaDB/chainer,niboshi/chainer,okuta/chainer,ysekky/chainer,cupy/cupy,okuta/chainer,sou81821/chainer,cupy/cupy,Kaisuke5/chainer,chainer/chainer,kiyukuta/chainer,hvy/chainer,chainer/chainer,t-abe/chainer,niboshi/chainer,benob/chainer,yanweifu/chainer,umitanuki/chainer,keisuke-umezawa/chainer,t-abe/chainer,minhpqn/chainer,tscohen/chainer,sinhrks/chainer,muupan/chainer,delta2323/chainer