Fix const-incorrectness in constructors of irtkCUGenericImage and warning regarding definition of USE_CUDA_NPP.
Fix const-incorrectness in constructors of irtkCUGenericImage and warning regarding definition of USE_CUDA_NPP.

ghisvail/irtk-legacy,BioMedIA/irtk-legacy,sk1712/IRTK,BioMedIA/IRTK,ghisvail/irtk-legacy,sk1712/IRTK,ghisvail/irtk-legacy,BioMedIA/irtk-legacy,BioMedIA/IRTK,BioMedIA/irtk-legacy,sk1712/IRTK,BioMedIA/irtk-legacy,sk1712/IRTK,ghisvail/irtk-legacy,BioMedIA/IRTK,BioMedIA/IRTK