trajectory_modification package
I added the trajectory_modification package.
The trajectory_modification package's publishers and subscribers have been set up to communicate with ramp_planner and trajectory_generator.
ramp_planner needs to have a modification request handler. The basic header code is there right now, but no implementation yet.
Once ramp_planner can send/receive trajectories to trajectory_modification in a structured way, the code for the modification operators will be worked on.