ENH: Add std::string support to tubeMessage
ENH: Add std::string support to tubeMessage

Change-Id: I80fd15a169c7727d92a9696cb15b610ac56e2ff9

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