Allow hotkey usage / autohide

[hackel]

This may be beyond the scope of this extension, if it is even possible at all, but I would find it very useful if I could still use menu hotkeys (alt-F, etc.) to bring up menus, even while the menu is "hidden". I don't know if this could be done by just setting the height to 0 or something instead of hiding the menu entirely. This is how Firefox works, and I find it very useful. Just a suggestion.

[stuaxo]

~~Pressing alt to show the menu bar would be pretty good.~~

Having alt toggle the menu bar like firefox would be great, it's not super usable as is.