[vtkusers] Support for 3D trackers and 3D mice

[Luis Sainz Hermoso]

Hi David!
	I've just developed a class based on
vtkWin32RenderWindowInteractor to allow the interaction between vtk and
the magellan SPACEMOUSE of logitech. It works quite fine (I'm still
working on it) except when I try to pan the camera.I would be really
greatful if you could send me the part of the code that pans the camera.

	Thank you very much

		Luis

P.S: I'm still working with vtk2.4 for compatibility reasons and I know
that with
vtk3.1 the interaction scheme has changed but I think there won't be any
problems in porting it.