ENH: Add option to disable sorting by size in itkRelabelComponentImageFilter

Adapted from abandoned patch, thanks Dzenan Zukic (http://review.source.kitware.com/#/c/8809/)
See also: https://issues.itk.org/jira/browse/ITK-3013

Change-Id: Ie66cc3bd8dfba25582d5bf5381c6fdcf7bce8495
Merge topic 'RelabelComponents'

8ea2b5fe ENH: Add option to disable sorting by size in itkRelabelComponentImageFilter