[vtkusers] VTK build instructions cleanup

[David Doria]

> For Visual Studio (which I use every day for 3+ years with vtk), I
> would argue to remove the INSTALL part and  BUILD_SHARED_LIBS because
> these prevent you from using both Debug and Release configurations in
> the visual studio ide. Since Release dlls are incompatible with Debug
> executables and visa versa. The incompatibility causes strange crashes
> on memory allocations / deallocations. Although that complicates the
> simple tutorial.
>
> John
>

That's ok, there should then just be an "advanced tutorial" :) - or at
least a "click here to see other options you may want to set" where
you could describe things like that.

David