Navigon has released an update to its turn-by-turn GPS navigation apps adding native iPad support, optional Zagat guide integration and a new Active Lane Assistant feature. MobileNavigator 1.7 is now a universal app supporting the iPhone and iPad 3G natively, the first major GPS navigation app to provide universal support in a single app. iPod touch and iPad Wi-Fi users can also use MobileNavigator with an external GPS accessory. Users can also now…