public BooleanProperty smoothingProperty() {
        if (null == smoothing) {
            smoothing = new BooleanPropertyBase(_smoothing) {
                @Override protected void invalidated() { fireTileEvent(REDRAW_EVENT); }
                @Override public Object getBean() { return Tile.this; }
                @Override public String getName() { return "smoothing"; }
            };
        }
        return smoothing;
    }
Defines if the smoothing property should be enabled/disabled.
At the moment this is only used in the SparkLineTileSkin and
RadarChartTileSkin.
@param SMOOTHING
src/main/java/eu/hansolo/tilesfx/Tile.java