Merge branch 'rfc-98-qwt6' into develop

CMake/FindQwt.cmake

Modules/ThirdParty/Qwt/otb-module-init.cmake

...Visualization/MonteverdiCore/src/ConfigureMonteverdi.h.in

...sualization/MonteverdiCore/src/mvdI18nCoreApplication.cxx

...ualization/MonteverdiGui/include/mvdHistogramPlotPicker.h

.../Visualization/MonteverdiGui/include/mvdHistogramWidget.h

...isualization/MonteverdiGui/src/mvdHistogramPlotPicker.cxx

...es/Visualization/MonteverdiGui/src/mvdHistogramWidget.cxx

SuperBuild/CMake/External_qwt.cmake

SuperBuild/CMakeLists.txt

SuperBuild/patches/QWT/qwtconfig.pri