* fix maxpool padding size

* restyle

* fix #1941 darknet2ncnn maxpool out_w issue

* fix typo caused build fail

* fix opencv4 c++11 flags in example folder

* fix #1542; fix avx2 uint16_t including

for #1542, it is for compatibility for opencv 2.x, such as on ubuntu 16.04 apt installed opencv

* Add yolov4 example option.
Add yolov4-tiny for benchmark.

* Restyled by astyle

* Restyled by clang-format

* Restyled by astyle

Co-authored-by: Restyled.io <commits@restyled.io>

* tf2sb

* wip

* wip

* concat maxpool avgpool

* StridedSlice

* handle stridedslice mask

* convert mlir deconvolution

* convert deconvolution output shape

* convert tanh

* code format

* Support yolov4-tiny conversion.
Add darknet2ncnn readme.
Add yolov4 example.

* Restyled by clang-format

* Restyled by astyle

* Restyled by clang-format

* Restyled by astyle

Co-authored-by: Restyled.io <commits@restyled.io>

* update roialign

* update tool for roialign

* fix ceil for roialign

* fix ios build

* fix

* fix

* make it compatibile with the old version

* fix ios build

* trigger CI

* fix test

* order

* build

* remove code

* merge roialign

* accelerate ROIAlign

* update note

* rename func

* roialign version

* trigger CI

* fix roialign

* use ref for pre-calc in roialign

* retrigger CI

* pre-alloc

* fuse mish and depthwise convolution

* darknet2ncnn: support enet-coco conversion.

* darknet2ncnn: Add an option, which is enabled by default, to merge all yolo output into one layer. The convert result is compatible with yolov3 example and can be used in benchmark.

* Add darknet to ncnn converter with YOLOv4 support.

* darknet2ncnn: add copyright info, fix clang compatibility

* fix wrong target

* darknet2ncnn: compatible with clang++ 9.0.0

Co-authored-by: zcy6735 <zcy6735@arcsoft.com.cn>