AStarDemo fix
AStar colors
astar record current closed cell
AStar add m_searchResult
fix search result
AStar refactor
c to clear obstacles
COST_ONE -> COST_STRAIGHT
横向纵向至少有一个可以展开才考虑斜向（两个都考虑就是别马脚算法）
remove isStartOrTargetCoord
step by step