swift3.0 实现对象拷贝

贡献者:赵大财
博客:https://my.oschina.net/zhaodacaiGitHub:https://github.com/dacaizhao
邮箱: [e-mail] QQ:327532817
=============================

//实现代理 NScopying

func copy(with zone: NSZone? = nil) -> Any {
        return type(of: self).init()
    }

//let myCollectionViewCell: YouCollectionViewCell = item[1].copy() as! YouCollectionViewCell