BUG: added more ImageMetadataInterface tests and fixed various bugs

...ine/OTB/Files/ioTvImageMetadataInterfaceTest_formosat.txt

...eline/OTB/Files/ioTvImageMetadataInterfaceTest_ikonos.txt

...ine/OTB/Files/ioTvImageMetadataInterfaceTest_pleiades.txt

...ne/OTB/Files/ioTvImageMetadataInterfaceTest_quickbird.txt

...seline/OTB/Files/ioTvImageMetadataInterfaceTest_spot5.txt

...line/OTB/Files/ioTvImageMetadataInterfaceTest_spot5_2.txt

...seline/OTB/Files/ioTvImageMetadataInterfaceTest_spot6.txt

...e/OTB/Files/ioTvImageMetadataInterfaceTest_worldview2.txt

Modules/Core/Metadata/include/otbDimapMetadataHelper.h

...Core/Metadata/include/otbFormosatImageMetadataInterface.h

...ore/Metadata/include/otbQuickBirdImageMetadataInterface.h

...les/Core/Metadata/include/otbSpotImageMetadataInterface.h

...s/Core/Metadata/src/otbFormosatImageMetadataInterface.cxx

...les/Core/Metadata/src/otbIkonosImageMetadataInterface.cxx

...es/Core/Metadata/src/otbImageMetadataInterfaceFactory.cxx

Modules/Core/Metadata/src/otbMetaDataKey.cxx

...s/Core/Metadata/src/otbPleiadesImageMetadataInterface.cxx

.../Core/Metadata/src/otbQuickBirdImageMetadataInterface.cxx

Modules/Core/Metadata/src/otbSpotImageMetadataInterface.cxx

Modules/Core/Metadata/test/CMakeLists.txt