Adds Chart getter to XChartPanel. Useful for changing the limits or style while updating series.

xchart/src/main/java/org/knowm/xchart/XChartPanel.java

@@ -93,6 +93,10 @@ public class XChartPanel extends JPanel {
     g2d.dispose();
   }
 
+  public Chart getChart() {
+    return this.chart;
+  }
+
   @Override
   public Dimension getPreferredSize() {
 
@@ -308,4 +312,4 @@ public class XChartPanel extends JPanel {
 
     return series;
   }
-}
\ No newline at end of file
+}