[vtkusers] Moving vtkCamera in local coordinates

[Surajit Nundy]

Hello,
	I would like to move a camera object in a coordinate system local to 
the camera object itself (say +z to move forward towards the focal 
point, etc).  void vtkCamera::SetPosition seems the only relevant 
method, but that moves the object in world coordinates.  Is there a 
method/object that does this?

Thanks,
Surajit Nundy