MRG: Merge branch 'contrast_enhancement' into develop

Modules/Applications/AppFiltering/app/CMakeLists.txt

.../Applications/AppFiltering/app/otbContrastEnhancement.cxx

Modules/Applications/AppFiltering/otb-module.cmake

Modules/Applications/AppFiltering/test/CMakeLists.txt

Modules/Filtering/Contrast/CMakeLists.txt

Modules/Filtering/Contrast/include/otbApplyGainFilter.h

Modules/Filtering/Contrast/include/otbApplyGainFilter.txx

...ering/Contrast/include/otbCLHistogramEqualizationFilter.h

...ing/Contrast/include/otbCLHistogramEqualizationFilter.txx

Modules/Filtering/Contrast/include/otbComputeGainLutFilter.h

...es/Filtering/Contrast/include/otbComputeGainLutFilter.txx

Modules/Filtering/Contrast/include/otbComputeHistoFilter.h

Modules/Filtering/Contrast/include/otbComputeHistoFilter.txx

Modules/Filtering/Contrast/otb-module.cmake

Modules/Filtering/Contrast/test/CMakeLists.txt

Modules/Filtering/Contrast/test/otbApplyGainFilter.cxx

Modules/Filtering/Contrast/test/otbApplyGainFilterNew.cxx

...tering/Contrast/test/otbCLHistogramEqualizationFilter.cxx

...ing/Contrast/test/otbCLHistogramEqualizationFilterNew.cxx

Modules/Filtering/Contrast/test/otbComputeGainLutFilter.cxx