* fix compiling failure on cxx14

* fix compile failure when NCNN_PIXEL off

* do not export pixel api when NCNN_PIXEL off

* disable squeezenet test when NCNN_PIXEL off

* do not build ncnn2table and examples when NCNN_PIXEL off

* make cmakedefine header independent

* restore platform.h.in

Co-authored-by: nihui <shuizhuyuanluo@126.com>
Co-authored-by: nihuini <nihuini@tencent.com>

* fix cmake 3.5.1 config error

* fix ubuntu16.04 build error

* vulkan cmake export templete

* 1) vulkan cmake dependency export. 2) support opencv_world import. 3) add BUILD_WITH_STATIC_CRT option

* Threads dependency

* NCNN_BUILD_WITH_STATIC_CRT option

* we do not support cmake before version 3.15 for option NCNN_BUILD_WITH_STATIC_CRT

* Update yolov4 example

Add streaming from OpenCV support.
Add time profiling support.
Improve error handling.

* fix #1941 darknet2ncnn maxpool out_w issue

* fix typo caused build fail

* fix opencv4 c++11 flags in example folder

* 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>

* 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>

* add folder property for a better looking in visual studio or other property supported IDEs

* fix condition for not found protobuf

* 1. capitalize to lowercase
2. rename visual folder 'test' to 'tests'

* update

* Update mobilenetv3ssdlite.cpp

* Update mobilenetv3ssdlite.cpp

* Update mobilenetv3ssdlite.cpp

* Add mobilenetv2_yolov3 ,and remove old model

* Recovery yolov2

* Update link

* Add peleenet+ssd+segmentation example

* Change normalize and mean

* Add segmentation demo

* Add add_executable

* Some errors

* Update flow

* Fixed a yolov3 resolution bug

* Set yolo defalut mean to 1.0