Inverse Dynamics FeedForward

The Inverse Dynamics Feed Forward update to Baxter's Joint Trajectory Action Server (JTAS) is meant to 

- Create smoother interpolated paths between trajectory points that are passed into the server by using Bezier curves. These curves keep the interpolated trajectory continuous in 3 dimensions (position, velocity, acceleration) for each joint
- Allow faster movements when using JTAS by feeding forward the trajectory's velocities and accelerations commands into the motor controller
- Maintain compatibility with trajectories that supply position-only trajectory points
Do we get the time of the last message of the limb joint states?  That might be a useful feature.