bayerutils: add new plugin with bayer2gray, to do caps conversion

This is a convenience function to avoid using a capssetter when we want to treat
Bayer as gray. In the future we can add properties to balance each element of the
CFA.

Note there's a bug with the in-place transform, so currently a memcpy is being used.

gst/bayerutils/CMakeLists.txt

@@ -0,0 +1,27 @@
+set (SOURCES
+  gstbayer2gray.c
+  )
+    
+set (HEADERS
+  gstbayer2gray.h)
+    
+include_directories (AFTER
+  )
+
+set (libname libgstbayerutils)
+
+add_library (${libname} MODULE
+  ${SOURCES}
+  ${HEADERS})
+  
+target_link_libraries (${libname}
+  ${GLIB2_LIBRARIES}
+  ${GOBJECT_LIBRARIES}
+  ${GSTREAMER_LIBRARY}
+  ${GSTREAMER_BASE_LIBRARY}
+  ${GSTREAMER_VIDEO_LIBRARY})
+  
+set (pdbfile "${CMAKE_CURRENT_BINARY_DIR}/\${CMAKE_INSTALL_CONFIG_NAME}/${libname}.pdb")
+install (FILES ${pdbfile} DESTINATION lib/gstreamer-1.0 COMPONENT pdb)
+install(TARGETS ${libname}
+  LIBRARY DESTINATION lib/gstreamer-1.0)