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/stitching/doc/autocalib.rst

@@ -30,4 +30,3 @@ Estimates focal lengths for each given camera.
     :param pairwise_matches: Matches between all image pairs.
 
     :param focals: Estimated focal lengths for each camera.
-

modules/stitching/doc/exposure_compensation.rst

@@ -108,4 +108,3 @@ Exposure compensator which tries to remove exposure related artifacts by adjusti
     };
 
 .. seealso:: :ocv:class:`detail::ExposureCompensator`
-

modules/stitching/doc/high_level.rst

@@ -208,4 +208,3 @@ Spherical warper factory class. ::
     };
 
 .. seealso:: :ocv:class:`detail::SphericalWarper`
-

modules/stitching/doc/stitching.rst

@@ -15,5 +15,3 @@ stitching. Images stitching
     seam_estimation
     exposure_compensation
     blenders
-
-

modules/stitching/doc/warpers.rst

@@ -260,4 +260,4 @@ Construct an instance of the cylindrical warper class.
 
 .. ocv:function:: void detail::CylindricalWarper::CylindricalWarper(float scale)
 
-    :param scale: Projected image scale multiplier
+    :param scale: Projected image scale multiplier