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

diff --cc doc/js_tutorials/js_setup/js_setup/js_setup.markdown
index 55fd40f,1a9ac76..7dfe1b0
--- 1/doc/js_tutorials/js_setup/js_setup/js_setup.markdown
--- 2/doc/js_tutorials/js_setup/js_setup/js_setup.markdown
+++ b/doc/js_tutorials/js_setup/js_setup/js_setup.markdown
@@@ -124,14 -128,14 +128,21 @@@ Building OpenCV.js from Sourc
  
      For example:
      @code{.bash}
-     python ./platforms/js/build_js.py build_js --build_test
+     emcmake python ./opencv/platforms/js/build_js.py build_js --build_test
+     @endcode
+ 
+ -#  [optional] To enable OpenCV contrib modules append `--cmake_option="-DOPENCV_EXTRA_MODULES_PATH=/path/to/opencv_contrib/modules/"`
+ 
+     For example:
+     @code{.bash}
+     python ./platforms/js/build_js.py build_js --cmake_option="-DOPENCV_EXTRA_MODULES_PATH=opencv_contrib/modules"
 +    @endcode
 +
 +-#  [optional] To enable OpenCV contrib modules append `--cmake_option="-DOPENCV_EXTRA_MODULES_PATH=/path/to/opencv_contrib/modules/"`
 +
 +    For example:
 +    @code{.bash}
 +    python ./platforms/js/build_js.py build_js --cmake_option="-DOPENCV_EXTRA_MODULES_PATH=opencv_contrib/modules"
      @endcode
  
  Running OpenCV.js Tests

diff --cc doc/tutorials/introduction/windows_install/windows_install.markdown
Simple merge

diff --cc modules/python/src2/cv2.cpp
Simple merge

diff --cc platforms/js/build_js.py
Simple merge

diff --cc platforms/winpack_dldt/build_package.py
Simple merge