Velocity control and teleop

I added a trajectory smoother and trajectory follower using velocity control in the jaco_ros package accessed by an action server (joint_velocity_controller), this provides smooth trajectories from MoveIt and is much more effective than the joint position based and Cartesian position based trajectory followers already implemented on the arm.  There are also various bugfixes and all of the action servers can now be safely preempted.  I also added the jaco_teleop package which includes joystick and keyboard teleop, as well as interactive markers for pose control and grasping. Finally, I included the jaco_model package so everything important is in one place within the jaco_ros repository.