DOC: Example inclusion for doxygen

Code/FeatureExtraction/otbBreakAngularPathListFilter.h

Code/FeatureExtraction/otbImageToSIFTKeyPointSetFilter.h

Code/FeatureExtraction/otbRemoveTortuousPathListFilter.h

Code/FeatureExtraction/otbRemoveWrongDirectionFilter.h

Code/FeatureExtraction/otbRoadExtractionFilter.h

Code/FeatureExtraction/otbSimplifyPathListFilter.h

Code/IO/otbDEMToImageGenerator.h

Code/IO/otbSpatialObjectDXFReader.h