This fixes#66.
Also adds Ctrl-Shift-Q to be able to quit via keyboard easily, but
prevent accidents.
Also move F1 and F2 keybinds to Alt+F1 and Alt+F2
respectively to also prevent accidents.
- This allows the user to enable/disable the frame flashing on new
messages.
- Some people find it massively distracting, but would still like
to receive notifications. Let's not force them to DND the app.