single pref win: move eip preferences to new combined preference window.
single pref win: enabled/disable services via preferences window, account page.
single pref win: moved password change UI to a separate window, opened from account page in preferences.
single pref win: gets the autopep8 beauty scrub.
single pref win: clean up vpn pref error displaying & don't show dummy gateways in case of error.
single pref win: move preference window tracking to PreferencesWindow
single pref win: minor linting & add changes file