[vtkusers] New FAQ entry for better performance and handling large data

[Ken Martin]

While I'm thinking of it... There is a new FAQ entry on how to handle large 
data sets and how to improve performance in VTK. You can find it at the 
link below:

http://public.kitware.com/cgi-bin/vtkfaq?req=show&file=faq03.007.htp

- Ken