[vtkusers] VTK Dart testing

[Maitland Bottoms]

It seems that the testing scripts want to write into the directories
under VTK_DATA_ROOT. Is that really the case? Or is there something I
can set via cmake to use a different testing scratch directory.

It would be best if VTK_DATA_ROOT could be read-only.

I am tracking down the errors in:
http://www.vtk.org/Testing/Sites/makapuu/Debian-vtk_4.0-1_i386.deb/20020908-2338-Experimental/Test.html

The other class of errors there seem to be side effects of running the
tests using xvfb-run to provide a virtual frame buffer instead of a
real X display.

-Maitland