When a user is not entering text into a prompt, the 'q' key should immediately
quit the application. On the other hand, the 'esc' key should cancel/close/go-back
to the previous context.
If we're at the surface level (nothing to cancel/close) and the user hits the
escape key, the default behaviour is to close the app, however we now have a
`quitOnTopLevelReturn` config key to override this.
I actually think from the beginning we should have made this config option
default to false rather than true which is the default this PR gives it,
but I don't want to anger too many people familiar with the existing behaviour.
845c80721f