make setitem mask to work with an arbitrary mask
make setitem mask to work with an arbitrary mask

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