* add universal intrinsics for HSV2RGB_b

* rewritten HSV2RGB_b without using extra universal intrinsics

* removed unused variable

* undo changes in v_load_deinterleave

fixes handling of empty matrices in some functions (#11634)

* a part of PR #11416 by Yuki Takehara

* moved the empty mat check in Mat::copyTo()

* fixed some test failures

* Update Intel's Inference Engine deep learning backend

* Remove cpu_extension dependency

* Update Darknet accuracy tests

Typo fixes (#11631)

Using codec->time_base is deprecated to specify muxer settings.
Resolves issue with FPS value for AVI files with FFmpeg 4.0.

Related FFmpeg commits:
- https://github.com/FFmpeg/FFmpeg/commit/194be1f43ea391eb986732707435176e579265aa
- https://github.com/FFmpeg/FFmpeg/commit/91736025b2807995e29bd0661807c1c84f515fef

Add Java and Python code for the following features2d tutorials: Harris corner detector, Shi-Tomasi corner detector, Creating your own corner detector, Detecting corners location in subpixels, Feature Detection, Feature Description, Feature Matching with FLANN, Features2D + Homography to find a known object. Use Lowe's ratio test to filter the matches.