ERR: Fixed nasty bug. vtkExtractVOI was calling AllocateScalars() *as
well as* CopyAllocate() (or PassThrough()) later on. This meant that subsequent filters saw 2 (two) arrays, one unnamed and empty, the other representing the real data. The unnamed array was able to crash at least the vtkStructuredPointsWriter and any of the vtkXMLWriters.