[vtkusers] Why does VTK throw so many 'casts away constness' warnings

[Kent Williams]

There are many, many warnings that come up when compiling VTK that all 
have the same source -- casting 'const char *' to 'char *'

Some of these problems come from calling third party functions, and VTK 
doesn't have any say in those 3rd party functions' const correctness.
Others come from passing string literals into functions taking 'char *' 
parameters.

In any case, VTK throws hundreds of warnings, which are distracting, and 
can be obscuring real problems that throw compiler warnings.
Is there anyone with write permission on the VTK CVS who cares enough to 
fix this?