when determining X-Axis height, consider all labels, not just the first one

xchart/src/main/java/com/xeiam/xchart/internal/chartpart/Axis.java

@@ -277,6 +277,12 @@ public class Axis implements ChartPart {
       // get some real tick labels
       AxisTickCalculator axisTickCalculator = axisTick.getAxisTickCalculator(workingSpace);
       String sampleLabel = axisTickCalculator.getTickLabels().get(0);
+      // find the longest String in all the labels
+      for (int i = 1; i < axisTickCalculator.getTickLabels().size(); i++) {
+        if (axisTickCalculator.getTickLabels().get(i).length() > sampleLabel.length()) {
+          sampleLabel = axisTickCalculator.getTickLabels().get(i);
+        }
+      }
 
       TextLayout textLayout = new TextLayout(sampleLabel, getChartPainter().getStyleManager().getAxisTickLabelsFont(), new FontRenderContext(null, true, false));
       AffineTransform rot =