* add interp param align_corner

add check support_vulkan after create_pipeline for tests

* code style

Co-authored-by: yangfengmax <yangfengmax@didichuxing.com>

* Add readme for keras2ncnn

* Add supported model variants

* Fix supported model variants

* fix vs2017 nmake warning C4267: 'initializing': conversion from 'size_t' to 'int'

* removewarn vs2017 nmake warning C4267: '+=': conversion from 'size_t' to 'int', possible loss of data

Co-authored-by: sf <sf@sf.sf>

* fix darknet2ncnn.cpp warnings

* revoke extra warning check

* 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

* 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