Merge remote-tracking branch 'origin/2.4' into merge-2.4

Conflicts:
	modules/core/src/gl_core_3_1.cpp
	modules/core/src/opencl/convert.cl
	modules/cudaimgproc/src/cuda/canny.cu
	modules/cudastereo/perf/perf_stereo.cpp
	modules/gpu/perf/perf_imgproc.cpp
	modules/gpu/test/test_denoising.cpp
	modules/ocl/src/opencl/imgproc_resize.cl
	samples/cpp/Qt_sample/main.cpp

modules/cudaimgproc/src/cuda/canny.cu

@@ -42,8 +42,6 @@
 
 #if !defined CUDA_DISABLER
 
-#include <utility>
-#include <algorithm>
 #include "opencv2/core/cuda/common.hpp"
 #include "opencv2/core/cuda/emulation.hpp"
 #include "opencv2/core/cuda/transform.hpp"
@@ -463,7 +461,10 @@ namespace canny
 
             count = min(count, map.cols * map.rows);
 
-            std::swap(st1, st2);
+            //std::swap(st1, st2);
+            short2* tmp = st1;
+            st1 = st2;
+            st2 = tmp;
         }
     }
 }