Merge commit '43aec5ad' into merge-2.4

Conflicts:
	cmake/OpenCVConfig.cmake
	cmake/OpenCVLegacyOptions.cmake
	modules/contrib/src/retina.cpp
	modules/gpu/doc/camera_calibration_and_3d_reconstruction.rst
	modules/gpu/doc/video.rst
	modules/gpu/src/speckle_filtering.cpp
	modules/python/src2/cv2.cv.hpp
	modules/python/test/test2.py
	samples/python/watershed.py

modules/androidcamera/camera_wrapper/camera_wrapper.h

@@ -14,4 +14,3 @@ double getCameraPropertyC(void* camera, int propIdx);
 void setCameraPropertyC(void* camera, int propIdx, double value);
 void applyCameraPropertiesC(void** camera);
 }
-

modules/androidcamera/include/camera_activity.hpp

@@ -44,4 +44,4 @@ private:
     int frameHeight;
 };
 
-#endif
+#endif