实现吃豆豆模型，能够监听键盘事件移动，判断吃否吃到豆豆，吃到一定数量会升级，会长大，速度会增加。-Only eat Peas model, able to monitor keyboard events move, to determine whether to eat eat Peas, eat a certain number will be upgraded, grow up, the speed will increase.

简单用linkedlist设计贪吃蛇，set设计豆豆，模拟贪吃蛇吃豆豆的功能-Linkedlist design Snake simple set design Peas, Analog Snake eat Peas