Remove JB bug fix for vtkImageData.
Remove JB bug fix for vtkImageData.

Defer resolution of scalar bug to subsequent refactoring if/when merged
into VTK master, i.e. when a common base class for probe and embedded
probe exists.
Issue #21

MSV-Project/MSVTK,MSV-Project/MSVTK,MSV-Project/MSVTK