Create KITTI IMU rosbag

[Joechencc]

I successfully construct a map using Lidar scan. Now I am working on the IMU integration on Lidar and IMU to optimize the map. However, the IMU seems have no effect on the result. I saw in IMUhandle, you only use roll and pitch to optimize the angle. I wonder if there should be any coordinate frame change when we construct the Rosbag