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/core/test/test_ds.cpp

@@ -2118,5 +2118,3 @@ TEST(Core_DS_Seq, sort_invert) { Core_SeqSortInvTest test; test.safe_run(); }
 TEST(Core_DS_Set, basic_operations) { Core_SetTest test; test.safe_run(); }
 TEST(Core_DS_Graph, basic_operations) { Core_GraphTest test; test.safe_run(); }
 TEST(Core_DS_Graph, scan) { Core_GraphScanTest test; test.safe_run(); }
-
-

modules/core/test/test_dxt.cpp

@@ -866,5 +866,3 @@ protected:
 };
 
 TEST(Core_DFT, complex_output) { Core_DFTComplexOutputTest test; test.safe_run(); }
-
-

modules/core/test/test_io.cpp

@@ -406,7 +406,7 @@ protected:
             Vec<int, 5> v1(15, 16, 17, 18, 19), ov1;
             Scalar sc1(20.0, 21.1, 22.2, 23.3), osc1;
             Range g1(7, 8), og1;
-            
+
             FileStorage fs(fname, FileStorage::WRITE);
             fs << "mi" << mi;
             fs << "mv" << mv;

modules/core/test/test_math.cpp

@@ -2755,4 +2755,3 @@ TEST(CovariationMatrixVectorOfMatWithMean, accuracy)
 }
 
 /* End of file. */
-