Transparency hotkey?

[wormyrocks]

On my fork of this project I added a short cut to toggle the window down to 50% opacity so you can read off a browser window under a fullscreen terminal.
Not fully integrated into the config ui, etc., but it works: https://github.com/wormyrocks/mintty-quake-console/

[lonepie]

I just submitted a pull request to bring these changes into my codebase. Let me know if that's ok!