Global plan is statically transformed to the global frame

[PaulVerhoeckx]

In TrackingPidLocalPlanner::setPlan() the passed global plan is transformed just once into the configured global_frame.
If this latter is configured to be odom, the global plan is sensitive to initial localisation faults.

Other planners (such as dwa_local_planner) convert the inserted global plan every tick into global_frame, using LocalPlannerUtil::getLocalPlan().