Simplify LSTM implementation
Simplify LSTM implementation

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