the float variant was always shadowed by the int version as
Rect2d is implicitly convertible to Rect.
This swaps things which is fine, as the vector of boxes was always
copied and the computation was done in double.

- python-3.x => python-3
- config-3.x.py => config-3.py

* Support Slice layer with multiple inputs

* Add test

* Supported Resize from PyTorch

* Rewrite test

* Remove Cast layer (supported in #16735)

* Support ConstantOfShape

* Fix tests

* Fix coments

* Remove useless condition

* Fixed failed tests

* Fixes issue 16777.

* core: update Concurrency getNumThreads()

  There's no need to use `vec_perm()` instead of `vec_splat()`,
  since instruction `vperm` is quite heavy compared to `vsplt[b,h,w]`.

* Supported Flatten for constant nodes

* Added default axis

* Refactoring

* Refactoring

* Added cast layer

* Fix comments

* Add Cast for layers

- HETERO plugin doesn't switch well between devices

- cache value, evaluate once
- better support for MINGW
- anything in 'cv' namespace
- test: dump number of active threads

* feature: Add video capture bitrate read-only property for FFMPEG backend

* test: For WIN32 property should be either expected or 0.

Added `IsOneOf` helper function, enabled only for _WIN32.

- Android Manager version is not increased (stuck on 3.49)

dnn(darknet-importer): add grouped convolutions, sigmoid, swish, scale_channels

* update darknet importer to support enetb0-yolo

* remove dropout (pr16438) and fix formatting

* add test for scale_channels

* disable batch testing for scale channels

* do not set LayerParams::name

* merge all activations into setActivation

* Add Tengine support .

* Modify printf to CV_LOG_WARNING

* a few minor fixes in the code

* Renew Tengine version

* Add header file for CV_LOG_WARNING

* Add #ifdef HAVE_TENGINE in tengine_graph_convolution.cpp

* remove trailing whitespace

* Remove trailing whitespace

* Modify for compile problem

* Modify some code style error

* remove whitespace

* Move some code style problem

* test

* add ios limit and build problem

* Modified as alalek suggested

* Add cmake 2.8 support

* modify cmake 3.5.1 problem

* test and set BUILD_ANDROID_PROJECTS OFF

* remove some compile error

* remove some extra code in tengine

* close test.

* Test again

* disable android.

* delete ndk version judgement

* Remove setenv() call . and add License information

* Set tengine default OFF. Close test .
Co-authored-by: NVadim Pisarevsky <vadim.pisarevsky@gmail.com>

Lets the user choose the maximum number of iterations the robust
estimator runs for, similary to findHomography. This can significantly
improve performance (at a computational cost).

ToT libc++ (LLVM) no longer includes <sstream>
as part of <complex> which breaks building opencv.
Include <sstream> header explcitly to fix this.

* core(logger): add CV_LOG_ONCE_xxx() CV_LOG_IF_xxx() macros

* core(logger): keep tests disabled

* imgproc(integral): avoid OOB access

* imgproc(test): fix integral perf check

- FP32 computation is not accurate

* imgproc(integral): tune loop limits

clGetSupportedImageFormats returns CL_INVALID_VALUE if called with
num_entries 0 and a non-NULL image_formats pointer so let's not do that.

* Supported Div op for constants

* Added Mul test

The hard-coded string value "Mat" was used in the two format strings for vector_mat and vector_mat_template, preventing UMat arguments to functions that have these types from working correctly. as noted in #12231.

- CMake option: OPENCV_DNN_IE_NN_BUILDER_2019

core: fix MatExpr::size() for gemm()

* core(test): MatExpr::size() test for gemm()

* core: fix MatExpr::size() for gemm()