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/ocl/include/opencv2/ocl/private/util.hpp

@@ -131,7 +131,7 @@ namespace cv
             {
                 openCLFree(tex_);
             }
-            operator cl_mem() 
+            operator cl_mem()
             {
                 return tex_;
             }