Fix FunctionSet.parameters and FunctionSet.gradients
Fix FunctionSet.parameters and FunctionSet.gradients

kikusu/chainer,ronekko/chainer,wkentaro/chainer,wkentaro/chainer,cupy/cupy,jnishi/chainer,niboshi/chainer,jnishi/chainer,ktnyt/chainer,hvy/chainer,hvy/chainer,keisuke-umezawa/chainer,AlpacaDB/chainer,okuta/chainer,benob/chainer,keisuke-umezawa/chainer,niboshi/chainer,kiyukuta/chainer,ktnyt/chainer,truongdq/chainer,cupy/cupy,cupy/cupy,wkentaro/chainer,keisuke-umezawa/chainer,niboshi/chainer,ktnyt/chainer,okuta/chainer,kashif/chainer,sinhrks/chainer,tkerola/chainer,rezoo/chainer,ysekky/chainer,chainer/chainer,cupy/cupy,niboshi/chainer,okuta/chainer,sinhrks/chainer,jnishi/chainer,hvy/chainer,chainer/chainer,t-abe/chainer,okuta/chainer,muupan/chainer,benob/chainer,aonotas/chainer,wkentaro/chainer,hvy/chainer,muupan/chainer,truongdq/chainer,delta2323/chainer,jnishi/chainer,t-abe/chainer,keisuke-umezawa/chainer,ktnyt/chainer,anaruse/chainer,chainer/chainer,kikusu/chainer,chainer/chainer,AlpacaDB/chainer,cemoody/chainer,pfnet/chainer