Changes added for stop operator
The fields stop_points and stop_times have been added to the Path object and msg. These are vectors corresponding to any points in a path (knot points) that we should stop at and for how long
Trajectory generation now considers stopping at a knot point. It check each segment to see if the ending knot point is one we should stop at. If so, it generates stopped motion states for the value in stop_time.
TODO: Trajectory generation - What if point 0 is a point to stop at? Planner - add finding the stop time calculation in Modifier class