Added sample configuration files that work for a 3D TV.

Copy the configuration files to the <Vrui-install-dir>/etc directory.
Run the device daemon using
  <Vrui-install-dir>/bin/VRDeviceDaemon -rootSection 3dtv
Run the VruiVTK application using
  VruiVTK -rootSection 3dtv

The configuration files work with an OptiTrack tracker with a VRPN server of
hostname "OptiTrackServer". The Rigid Body Module is used to configure two rigid
bodies, namely, Head and Wand.