COMP: Fixed signed/unsigned warnings
COMP: Fixed signed/unsigned warnings

thewtex/TubeTK,aylward/ITKTubeTK,aylward/ITKTubeTK,KitwareMedical/ITKTubeTK,thewtex/TubeTK,KitwareMedical/ITKTubeTK,KitwareMedical/ITKTubeTK,KitwareMedical/ITKTubeTK,aylward/ITKTubeTK,thewtex/TubeTK,thewtex/TubeTK,aylward/ITKTubeTK