Merge topic 'UseITKFilterWatcher'

4092ac6 ENH: Use ITK FilterWatcher and rename DifferenceImageFilter2
ENH: Use itkMacro.h instead of tubeMacro.h

tubeMacro.h is very rarely used and itkMacro.h contains at least the same
functionality, so always use itkMacro.h.

Change-Id: Ic8a0293aaffc605cc4b9c94a90d6b5b4ea995fdf
WIP: ITKMetaDocuments

Change-Id: Ib53e8e82fd28a510e82d66837f20790866d0b312