* runtime cpu dispatch

* force thread one

* disable openmp for coverage

* simplify test layer

* print NCNN_TARGET_ARCH

* less ci build variants

* weight fp16 storage option

* test convdw int8

* apple a12 a13

* ncnn_add_layer ncnn_add_shader cmake macro

* update readme: metion yolact, retinaface, etc

* update doc: add c/cpp/python for code region

* delete ccpp.yml

* add build.yml

* split all workflows

* delete single file defined workflows

* light up the building status matrix

* use short icons

* add actions to ios 32bit cpu position

* rename ios workflow file's name

* rename ios workflow name

* Add mips architecture optimization support

* Add mipsisa32r6 toolchain files

* Add AbsVal_mips layer

* Remove unused constructor override

* Keep the same programming style with upstream

* Add Bias_mips layer

* Add Clip_mips layer

* Update copyright header

* Add mips-mti-gnu compile to travis

* Add codescape mips toolchain config

* Update the toolchain comments

* Fix conflicts in travis config file

* Add travis status in README.md

* adding how to build for jetson

* update build instruction for NVIDIA Jetson