Stop operator added
Path msg had 2 fields added - stop_points and stop_times. Both are uint32 vectors corresponding to the knot points where stops occur and for how long they occur, respectively.
Path modification package is only called when the operator affects the path. The stop operator does not. A separate method was added to the ramp_planner Modifier class to deal with stop operations. This package also had to remove the values in a Path's stop_points and stop_times vectors if a Delete operation was performed. TODO: What if crossover?
Trajectory generator package had numerous changes to generate trajectories that can handle stops of any time at each knot point (except the last). The total stop time is added to the segment's T_min so that the correct knot points are obtained for a trajectory with stops in it.
If a new msg is created for knot points, it may make the code cleaner because there will be less maintanence for a Path's stop_points and stop_times vectors.