Add developer shortcut to reload chrome files

Hitting Ctrl+Shift+C will re-initialize the chrome provider,
reloading all chrome files instantly. Useful when changing the
UI.

Note: A new "RootWidget" was created to trap top-level (global)
shortcuts instead of putting everything in Widget.
> You could do this using LogicKeyListenerWidget

There's no yaml file for the "root" widget, is there?