v0.45-beta

an improved version based on the project https://github.com/flow-project/flow
adding 1 new roadnetwork(multi-lane grid network). 2 new router(for env-vehicles and for CAVs),1 new grid scenario in which CAV travels through fixed-time intersections under environment traffic-flow of HVs. CAV can reroute due to expected shortest travel time every 600 simulation steps.

基于https://github.com/flow-project/flow项目的改进版
新增了一个新的路网（多车道方格路网），两个新的车辆路径规划功能（分别给环境车辆和CAV），一个新的方格路网场景，其中CAV在固定配时信号灯下的环境车流中行驶，每600步长基于最小期望时间改变一次预期路径。