Unreal Lidar incorrectly casting traces

[WouterJansen]

Steps to reproduce bug:

• Create a lidar sensor with an offset location from the vehicle origin
• Turn on DrawDebugPoints for observing more easily the problem
• Drive/fly the car/drone and make sure to rotate
• Observe the incorrect lidar pointcloud being made

Reason:
UnrealLidarSensor::shootLaser() in UnrealLidarSensor.cpp creates the starting location of the trace as
Vector3r start = lidar_pose.position + vehicle_pose.position; (currently line 113)

If the lidar does not share the vehicle origin's X and Y position, this will start introducing an incorrect starting position for the trace as the vehicle starts rotating as the rotation of vehicle/lidar is completely ignored.

Fix:
To fix one can change this line to
Vector3r start = VectorMath::add(lidar_pose, vehicle_pose).position;

[ironclownfish]

Thanks, PR approved!