issue #32. place warning for user to clean up the data.

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

@@ -88,11 +88,11 @@ public class ChartPainter {
       throw new RuntimeException("No series defined for Chart!!!");
     }
     if (getStyleManager().isXAxisLogarithmic() && axisPair.getxAxis().getMin().compareTo(BigDecimal.ZERO) <= 0) {
-      throw new IllegalArgumentException("Series data cannot be less or equal to zero for a logarithmic X-Axis!!!");
+      throw new IllegalArgumentException("Series data (accounting for error bars too) cannot be less or equal to zero for a logarithmic X-Axis!!!");
     }
     if (getStyleManager().isYAxisLogarithmic() && axisPair.getyAxis().getMin().compareTo(BigDecimal.ZERO) <= 0) {
       // System.out.println(axisPair.getyAxis().getMin());
-      throw new IllegalArgumentException("Series data cannot be less or equal to zero for a logarithmic Y-Axis!!!");
+      throw new IllegalArgumentException("Series data (accounting for error bars too) cannot be less or equal to zero for a logarithmic Y-Axis!!!");
     }
 
     g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); // global rendering hint