traditional Chinese localization, string extraction, icon clone and resize

1. add zh-tw for traditional Chinese Language
2. extract some hard-code string to resource file
3. clone rssi-icon to radio-icon and resize radio-icon to the same size with other menu-icon
@metalnow `FlightMapFragment`'s parent has a protected `Drone` instance, so you can use that instead(i.e: `this.drone`).