* update build instruction for legacy Windows
* add CI build for windows legacy
* merge mingw CI builds
* merge deb CI builds
* fix typo
* bump qt 5.6 build
* update arch linux deps; make it CI-friendly
* fix musl compatibility
* alpine linux packaging
* add musl-based Linux to CI
* update rpm build
* update doc
* improve Qt 5.6 support
* switch registry API to Windows XP compatible Unicode API
* update docs
* add comment for `CONFIG += c++14 c++17` in qmake .pro files
* fix logic for lockFile
* add runner args abstraction to allow different args patterns in various terminal apps; fix macOS shm IPC
* extend platform support from Linux to XDG desktop
* update build docs for Unix
* improve terminal args pattern migration for macOS
* Arch Linux packaging; make LIBEXECDIR configurable
* update docs
* resolve libexec and share from relative path
* AppImage packaging
* allow build AppImage on Windows host