Avoid temporary std::string instance in dtype.char
Avoid temporary std::string instance in dtype.char

niboshi/chainer,keisuke-umezawa/chainer,jnishi/chainer,hvy/chainer,wkentaro/chainer,tkerola/chainer,wkentaro/chainer,ktnyt/chainer,okuta/chainer,hvy/chainer,keisuke-umezawa/chainer,chainer/chainer,jnishi/chainer,hvy/chainer,niboshi/chainer,niboshi/chainer,ktnyt/chainer,wkentaro/chainer,niboshi/chainer,keisuke-umezawa/chainer,chainer/chainer,okuta/chainer,okuta/chainer,chainer/chainer,chainer/chainer,keisuke-umezawa/chainer,pfnet/chainer,ktnyt/chainer,wkentaro/chainer,jnishi/chainer,jnishi/chainer,ktnyt/chainer,okuta/chainer,hvy/chainer