numpy backward compatibility (boolean array-like index)
numpy backward compatibility (boolean array-like index)

keisuke-umezawa/chainer,chainer/chainer,chainer/chainer,hvy/chainer,niboshi/chainer,wkentaro/chainer,niboshi/chainer,wkentaro/chainer,keisuke-umezawa/chainer,hvy/chainer,okuta/chainer,okuta/chainer,hvy/chainer,wkentaro/chainer,hvy/chainer,wkentaro/chainer,okuta/chainer,keisuke-umezawa/chainer,keisuke-umezawa/chainer,chainer/chainer,pfnet/chainer,chainer/chainer,niboshi/chainer,okuta/chainer,niboshi/chainer