Ajout classes pour calcul d'indice de vegetation pour 3 canaux. Dev du functor ARVI

...ry/otbMultiChannelRAndBAndNIRVegetationIndexImageFilter.h

.../otbMultiChannelRAndBAndNIRVegetationIndexImageFilter.txx

Code/Radiometry/otbRAndBAndNIRVegetationIndexImageFilter.h

Code/Radiometry/otbRAndBAndNIRVegetationIndexImageFilter.txx

Code/Radiometry/otbRAndNIRVegetationIndexImageFilter.txx

Code/Radiometry/otbVegetationIndex.h

Testing/Code/Radiometry/CMakeLists.txt

.../otbMultiChannelRAndBAndNIRVegetationIndexImageFilter.cxx

...bMultiChannelRAndBAndNIRVegetationIndexImageFilterNew.cxx

...e/Radiometry/otbRAndBAndNIRVegetationIndexImageFilter.cxx

...adiometry/otbRAndBAndNIRVegetationIndexImageFilterNew.cxx

Testing/Code/Radiometry/otbRadiometryTests.cxx