[ITK] ThresholdImageFilter on VectorImage

[David Froger]

It works using a combination of:
  - VectorIndexSelectionCastImageFilter
  - ThresholdImageFilter
  - ImageDuplicator
  - ComposeImageFilter

  https://github.com/dfroger/issue/blob/66a6585/itk/main3.cxx

But not simple nor efficient.