* see /Vision/Data/kitti_velodyne

* velodyne_pcl is not required anymore in ROS wrapping : point types are added to
external_include in conversion package. /!\ Warning this implies a dupplication of the point type files and must be updated with the drivers.

* The launch file is precised to be velodyne relative and the driver can
be launched if needed

* The user can directly read velodyne pcap files with this launch file