Merge remote-tracking branch 'upstream/3.4' into merge-3.4

diff --cc CMakeLists.txt
Simple merge

diff --cc doc/tutorials/core/file_input_output_with_xml_yml/file_input_output_with_xml_yml.markdown
index e74f770,4e426c6..b71fbeb
--- 1/doc/tutorials/core/file_input_output_with_xml_yml/file_input_output_with_xml_yml.markdown
--- 2/doc/tutorials/core/file_input_output_with_xml_yml/file_input_output_with_xml_yml.markdown
+++ b/doc/tutorials/core/file_input_output_with_xml_yml/file_input_output_with_xml_yml.markdown
@@@ -17,15 -17,27 +17,27 @@@ You'll find answers for the following q
  
  Source code
  -----------
- 
+ @add_toggle_cpp
  You can [download this from here
 -](https://github.com/opencv/opencv/tree/3.4/samples/cpp/tutorial_code/core/file_input_output/file_input_output.cpp) or find it in the
 +](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/core/file_input_output/file_input_output.cpp) or find it in the
  `samples/cpp/tutorial_code/core/file_input_output/file_input_output.cpp` of the OpenCV source code
  library.
  
  Here's a sample code of how to achieve all the stuff enumerated at the goal list.
  
  @include cpp/tutorial_code/core/file_input_output/file_input_output.cpp
 -](https://github.com/opencv/opencv/tree/3.4/samples/python/tutorial_code/core/file_input_output/file_input_output.py) or find it in the
+ @end_toggle
+ 
+ @add_toggle_python
+ You can [download this from here
++](https://github.com/opencv/opencv/tree/master/samples/python/tutorial_code/core/file_input_output/file_input_output.py) or find it in the
+ `samples/python/tutorial_code/core/file_input_output/file_input_output.py` of the OpenCV source code
+ library.
+ 
+ Here's a sample code of how to achieve all the stuff enumerated at the goal list.
+ 
+ @include python/tutorial_code/core/file_input_output/file_input_output.py
+ @end_toggle
  
  Explanation
  -----------

diff --cc doc/tutorials/video/meanshift/meanshift.markdown
index c0e7458,5b2d789..c51b8fc
--- 1/doc/tutorials/video/meanshift/meanshift.markdown
--- 2/doc/tutorials/video/meanshift/meanshift.markdown
+++ b/doc/tutorials/video/meanshift/meanshift.markdown
@@@ -57,6 -57,14 +57,14 @@@ low light, low light values are discard
      @include samples/python/tutorial_code/video/meanshift/meanshift.py
  @end_toggle
  
 -    [here](https://github.com/opencv/opencv/tree/3.4/samples/java/tutorial_code/video/meanshift/MeanshiftDemo.java)
+ @add_toggle_java
+ -   **Downloadable code**: Click
++    [here](https://github.com/opencv/opencv/tree/master/samples/java/tutorial_code/video/meanshift/MeanshiftDemo.java)
+ 
+ -   **Code at glance:**
+     @include  samples/java/tutorial_code/video/meanshift/MeanshiftDemo.java
+ @end_toggle
+ 
  Three frames in a video I used is given below:
  
  ![image](images/meanshift_result.jpg)
@@@ -98,6 -106,14 +106,14 @@@ parameters (used to be passed as searc
      @include samples/python/tutorial_code/video/meanshift/camshift.py
  @end_toggle
  
 -    [here](https://github.com/opencv/opencv/tree/3.4/samples/java/tutorial_code/video/meanshift/CamshiftDemo.java)
+ @add_toggle_java
+ -   **Downloadable code**: Click
++    [here](https://github.com/opencv/opencv/tree/master/samples/java/tutorial_code/video/meanshift/CamshiftDemo.java)
+ 
+ -   **Code at glance:**
+     @include  samples/java/tutorial_code/video/meanshift/CamshiftDemo.java
+ @end_toggle
+ 
  Three frames of the result is shown below:
  
  ![image](images/camshift_result.jpg)

diff --cc doc/tutorials/video/optical_flow/optical_flow.markdown
index d480976,d7a6896..8dc86d9
--- 1/doc/tutorials/video/optical_flow/optical_flow.markdown
--- 2/doc/tutorials/video/optical_flow/optical_flow.markdown
+++ b/doc/tutorials/video/optical_flow/optical_flow.markdown
@@@ -109,6 -109,15 +109,15 @@@ below
      @include samples/python/tutorial_code/video/optical_flow/optical_flow.py
  @end_toggle
  
 -    [here](https://github.com/opencv/opencv/tree/3.4/samples/java/tutorial_code/video/optical_flow/OpticalFlowDemo.java)
+ 
+ @add_toggle_java
+ -   **Downloadable code**: Click
++    [here](https://github.com/opencv/opencv/tree/master/samples/java/tutorial_code/video/optical_flow/OpticalFlowDemo.java)
+ 
+ -   **Code at glance:**
+     @include samples/java/tutorial_code/video/optical_flow/OpticalFlowDemo.java
+ @end_toggle
+ 
  (This code doesn't check how correct are the next keypoints. So even if any feature point disappears
  in image, there is a chance that optical flow finds the next point which may look close to it. So
  actually for a robust tracking, corner points should be detected in particular intervals. OpenCV
@@@ -151,6 -160,15 +160,15 @@@ corresponds to Value plane. See the cod
  @end_toggle
  
  
 -    [here](https://github.com/opencv/opencv/tree/3.4/samples/java/tutorial_code/video/optical_flow/OpticalFlowDenseDemo.java)
+ @add_toggle_java
+ -   **Downloadable code**: Click
++    [here](https://github.com/opencv/opencv/tree/master/samples/java/tutorial_code/video/optical_flow/OpticalFlowDenseDemo.java)
+ 
+ -   **Code at glance:**
+     @include samples/java/tutorial_code/video/optical_flow/OpticalFlowDenseDemo.java
+ @end_toggle
+ 
+ 
  See the result below:
  
  ![image](images/opticalfb.jpg)

diff --cc modules/core/src/arithm.cpp
Simple merge

diff --cc modules/core/src/arithm.simd.hpp
Simple merge

diff --cc modules/dnn/src/tensorflow/tf_graph_simplifier.cpp
Simple merge

diff --cc modules/dnn/src/tensorflow/tf_importer.cpp
Simple merge

diff --cc modules/imgcodecs/src/utils.cpp
Simple merge