Add the early stopping example
Add the early stopping example

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