Add atexit code
Add atexit code

delta2323/chainer,okuta/chainer,keisuke-umezawa/chainer,jnishi/chainer,cupy/cupy,cupy/cupy,cupy/cupy,chainer/chainer,jnishi/chainer,hvy/chainer,hvy/chainer,ronekko/chainer,keisuke-umezawa/chainer,niboshi/chainer,hvy/chainer,aonotas/chainer,okuta/chainer,keisuke-umezawa/chainer,wkentaro/chainer,jnishi/chainer,okuta/chainer,kashif/chainer,pfnet/chainer,chainer/chainer,kiyukuta/chainer,wkentaro/chainer,rezoo/chainer,niboshi/chainer,keisuke-umezawa/chainer,hvy/chainer,ysekky/chainer,niboshi/chainer,ktnyt/chainer,wkentaro/chainer,cupy/cupy,niboshi/chainer,ktnyt/chainer,ktnyt/chainer,wkentaro/chainer,tkerola/chainer,anaruse/chainer,chainer/chainer,chainer/chainer,jnishi/chainer,ktnyt/chainer,okuta/chainer