Include `installer` for stable releases

[musjj]

The installer folder contains a lot of useful scripts for setting up mpv:

./mpv/installer
├── configure-opengl-hq.bat
├── mpv-icon.ico
├── mpv-install.bat
├── mpv-uninstall.bat
└── updater.ps1

But they are only included in the nightly releases. Can we also have them in the stable releases?

[chortbauer]

I came here to ask exactly the same thing.

[candrapersada]

how to use single instance mode in mpv-install.bat

[hooke007]

There is no such mode in mpv.