#5 OTRproxy "quit" menu items are broken

[Len Sassaman]

The "File --> Quit" menu item does nothing, and should not be
present. I am not sure what Apple's style conventions say about
empty File menus -- this is unusual -- but "Quit" no longer belongs
there.

The "otrproxy --> Quit" menu item lacks the keyboard shortcut
"Command-Q" associated with it, and thus otrproxy cannot be quit
from the keyboard. This should be fixed.