Add unittest for binary operators where arguments are numpy.ndarray and Variable
Add unittest for binary operators where arguments are numpy.ndarray and Variable

Some unitests are commented out. See #43.

jfsantos/chainer,elviswf/chainer,umitanuki/chainer,cemoody/chainer,cupy/cupy,jnishi/chainer,okuta/chainer,wkentaro/chainer,benob/chainer,minhpqn/chainer,wkentaro/chainer,okuta/chainer,ktnyt/chainer,jnishi/chainer,keisuke-umezawa/chainer,muupan/chainer,kikusu/chainer,cupy/cupy,okuta/chainer,ronekko/chainer,wkentaro/chainer,bayerj/chainer,kuwa32/chainer,chainer/chainer,chainer/chainer,hvy/chainer,woodshop/complex-chainer,cupy/cupy,ktnyt/chainer,chainer/chainer,jnishi/chainer,ysekky/chainer,laysakura/chainer,niboshi/chainer,keisuke-umezawa/chainer,tereka114/chainer,muupan/chainer,woodshop/chainer,ytoyama/yans_chainer_hackathon,tscohen/chainer,sinhrks/chainer,niboshi/chainer,keisuke-umezawa/chainer,aonotas/chainer,kiyukuta/chainer,masia02/chainer,tkerola/chainer,sou81821/chainer,sinhrks/chainer,niboshi/chainer,yanweifu/chainer,cupy/cupy,t-abe/chainer,hidenori-t/chainer,AlpacaDB/chainer,AlpacaDB/chainer,t-abe/chainer,1986ks/chainer,okuta/chainer,wavelets/chainer,keisuke-umezawa/chainer,truongdq/chainer,Kaisuke5/chainer,jnishi/chainer,hvy/chainer,ktnyt/chainer,ktnyt/chainer,kashif/chainer,truongdq/chainer,pfnet/chainer,tigerneil/chainer,anaruse/chainer,benob/chainer,hvy/chainer,wkentaro/chainer,niboshi/chainer,kikusu/chainer,ikasumi/chainer,chainer/chainer,delta2323/chainer,rezoo/chainer,hvy/chainer