doxygen: exclude licensing comments

indra/media_plugins/gstreamer010/llmediaimplgstreamer.h

.../media_plugins/gstreamer010/llmediaimplgstreamer_syms.cpp

indra/media_plugins/gstreamer010/llmediaimplgstreamer_syms.h

...plugins/gstreamer010/llmediaimplgstreamertriviallogging.h

...edia_plugins/gstreamer010/llmediaimplgstreamervidplug.cpp

.../media_plugins/gstreamer010/llmediaimplgstreamervidplug.h

.../media_plugins/gstreamer010/media_plugin_gstreamer010.cpp

indra/media_plugins/quicktime/media_plugin_quicktime.cpp

indra/media_plugins/webkit/media_plugin_webkit.cpp