Turn off VRPN debugging.  Improve handling of the case when no buttons or no trackers are configured.
Turn off VRPN debugging.  Improve handling of the case when no buttons
or no trackers are configured.

Submitted by:	Anthony Steed <A dot Steed at cs dot ucl dot ac dot uk>


git-svn-id: 769d22dfa2d22aad706b9a451492fb87c0735f19@15569 08b38cba-cd3b-11de-854e-f91c5b6e4272

godbyk/vrjuggler-upstream-old,MichaelMcDonnell/vrjuggler,LiuKeHua/vrjuggler,vancegroup-mirrors/vrjuggler,godbyk/vrjuggler-upstream-old,MichaelMcDonnell/vrjuggler,vrjuggler/vrjuggler,MichaelMcDonnell/vrjuggler,vrjuggler/vrjuggler,LiuKeHua/vrjuggler,godbyk/vrjuggler-upstream-old,vancegroup-mirrors/vrjuggler,LiuKeHua/vrjuggler,MichaelMcDonnell/vrjuggler,LiuKeHua/vrjuggler,LiuKeHua/vrjuggler,vrjuggler/vrjuggler,LiuKeHua/vrjuggler,MichaelMcDonnell/vrjuggler,vrjuggler/vrjuggler,vrjuggler/vrjuggler,MichaelMcDonnell/vrjuggler,godbyk/vrjuggler-upstream-old,MichaelMcDonnell/vrjuggler,MichaelMcDonnell/vrjuggler,godbyk/vrjuggler-upstream-old,vancegroup-mirrors/vrjuggler,godbyk/vrjuggler-upstream-old,LiuKeHua/vrjuggler,LiuKeHua/vrjuggler,vrjuggler/vrjuggler,vancegroup-mirrors/vrjuggler,vrjuggler/vrjuggler,vancegroup-mirrors/vrjuggler,vrjuggler/vrjuggler,vancegroup-mirrors/vrjuggler