8个方向的Astart寻路算法，在原来代码基础改动,8 direction Astart pathfinding algorithm, changes in the original code base

简单的A-star寻路算法，给出了几种不同的地图，并得到正确的寻路结果-A-star a simple routing algorithm, are given several different types of maps, and the results of the correct routing