管理双向链表的一个类，支持整形，浮点型，字符型，字符串等，能够很方便的增加自定义类型，能动态增加，删除任何位置的元素-Management of a class of two-way linked list to support the plastic, floating-point type, character, string and so on, can easily customize the type of increase that can dynamically add, dele