add dummy joint trajectory server and update demo_sim.launch

When I found demo_sim.launch, I thought this is the launch file for those who do not have real baxter nor baxter gazebo simulation, but it seems not.
One easiest solution is to set `allow_trajectory_execution` to false (http://moveit.ros.org/wiki/MoveGroup_Node) to disable `Execute` button. but I do no like to see the baxter in the rviz is still in initial position.
If MoveIt! provides something like loopback trajectory execution, that just to update robot posture from trajectory execution, I'd like to use that.

This PR contains joint_trajectory_controller that takes FollowJointTrajectory and publishes joint states, so if you launch demo_sim.launch, you can use MoveIt without realrobot/gazebo.
ok, I fixed and changed the file name.

> On a similar note, demo_sim.launch is a misleading name for this file to
begin with. It should be something similar to demo_dummy.launch or
baxter_dummy.lauch.

I renamed existing demo_sim.launch to demo_dummy.launch. Is this correct?
or should I create new file named demo_dummy.launch along with existing
demo_sim.launch?


--
◉ Kei Okada


On Sat, Dec 13, 2014 at 3:46 AM, Ian McMahon <notifications@github.com>
wrote:

> In baxter/baxter_moveit_config/scripts/joint_trajectory_controller
> <https://github.com/ros-planning/moveit_robots/pull/24#discussion-diff-21764147>
> :
>
> > +
> > +
> > +
> > +
> > +"""
> > +IndustrialRobotSimulator
> > +
> > +This class simulates an industrial robot controller.  The simulator
> > +adheres to the ROS-Industrial robot driver specification:
> > +
> > +http://www.ros.org/wiki/Industrial/Industrial_Robot_Driver_Spec
> > +
> > +TODO: Currently the simulator only supports the bare minimum motion
> > +interface.
> > +
> > +TODO: Interfaces to add:
>
> Hmm. Are any of these comments relevant to this fake Baxter JTAS?
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/ros-planning/moveit_robots/pull/24/files#r21764147>.
>