Check that waypoint times are strictly increasing

A precondition for all trajectories executed by the
joint_trajectory_controller is that waypoints must have strictly
increasing reach times. This changeset validates the precondition and
rejects commands that don't satisfy it.
Add missing dependency to tests target
Merge pull request #146 from pal-robotics/check-waypoint-timing-hydro

Check waypoint timing. Hydro backport