Settings: add USB Tether tile

    <string name="qs_tile_lte">LTE</string>

    <string name="qs_tile_visualizer" translatable="false">AudioFX</string>

    <string name="qs_tile_screen_timeout">Screen timeout</string>

    <string name="qs_tile_usb_tether">USB tethering</string>

    <string name="qs_main_tiles_title">Enlarge first row</string>

    <string name="qs_main_tiles_summary_on">Two main tiles on the first row</string>

                resourceName ="ic_livedisplay_day";

                stringId = R.string.live_display_title;

                break;

            case QSConstants.TILE_USB_TETHER:

                resourceName = "ic_qs_usb_tether_on";

                stringId = R.string.qs_tile_usb_tether;

                break;

            default:

                return null;

        }