Added minimap which shows all players' positions. Currently just support basement, only for testing now, not finished yet. Don't delete img folder when you have unzipped, it contains images of maps. 添加了小地图窗口，可以显示所有玩家的位置，目前只支持地下室地图。当前该功能正处于测试阶段，后续会完善UI和相关代码。 不要删除解压后的img文件夹，它包含地图文件