Put simple widgets into the HUD

[ripefig]

The HUD is reliant on the presence of the Global Menu, which is less than ideal. What if clickable menus and buttons were integrated into the HUD? You'd probably have to move to GTK+ or QT to do this.

Mockups here: https://medium.com/@leftcrane/gui-hud-using-global-menu-features-hacks-572760272168

Further note:
If the HUD is extensible enough and implements KDE's DWD protocol, it could also display much more than just menu items even. In combination with server-side headerbars it could finally bring consistency to most Linux apps. (details here: https://medium.com/@leftcrane/unity-headers-concept-using-server-side-hearderbars-to-create-a-consistent-customizable-and-fbdb0d9696c)

(I am confident that there is a big need for such a project and that many users would donate money to get a good solution.)