WRG: Fixing a bunch of warnings

Modules/Applications/AppFiltering/app/otbDespeckle.cxx

Modules/Applications/AppFusion/app/otbPansharpening.cxx

...s/Applications/AppImageUtils/app/otbDownloadSRTMTiles.cxx

...alObjects/include/otbImageToLineSpatialObjectListFilter.h

...les/Filtering/MathParser/include/otbBandMathImageFilter.h

...rspectral/Unmixing/include/otbSparseUnmixingImageFilter.h

Modules/IO/TestKernel/src/otbTestHelper.cxx

...Calibration/test/otbAtmosphericCorrectionSequencement.cxx

...aniaReflectanceToRomaniaSurfaceReflectanceImageFilter.cxx

.../test/otbSurfaceAdjacencyEffectCorrectionSchemeFilter.cxx

...on/Conversion/include/otbVectorDataToLabelImageFilter.txx