Some simple itkNotUsed(...) to fix warnings that came up on Mac.
Some simple itkNotUsed(...) to fix warnings that came up on Mac.

Change-Id: I4b2a3a7d05c59b06e3ed2dbf1b5d224b02352ee4

cdeepakroy/TubeTK,KitwareMedical/ITKTubeTK,sumedhasingla/TubeTK,cdeepakroy/TubeTK,KitwareMedical/TubeTK,KitwareMedical/ITKTubeTK,KitwareMedical/TubeTK,aylward/ITKTubeTK,thewtex/TubeTK,aylward/ITKTubeTK,sumedhasingla/TubeTK,KitwareMedical/TubeTK,thewtex/TubeTK,sumedhasingla/TubeTK,KitwareMedical/ITKTubeTK,KitwareMedical/ITKTubeTK,thewtex/TubeTK,cdeepakroy/TubeTK,aylward/ITKTubeTK,LucasGandel/TubeTK,KitwareMedical/TubeTK,matthieuheitz/TubeTK,cdeepakroy/TubeTK,aylward/ITKTubeTK,matthieuheitz/TubeTK,LucasGandel/TubeTK,matthieuheitz/TubeTK,matthieuheitz/TubeTK,LucasGandel/TubeTK,thewtex/TubeTK,LucasGandel/TubeTK,sumedhasingla/TubeTK