Fix for GDI crash if stroke-dasharray contains value<=0

GDI Pen was crashing with some bad (Adobe Illustrator) data that had: stroke-dasharray="10,10,0"

Source/Basic Shapes/SvgVisualElement.cs

@@ -163,7 +163,7 @@ namespace Svg
                     if (this.StrokeDashArray != null && this.StrokeDashArray.Count > 0)
                     {
                         /* divide by stroke width - GDI behaviour that I don't quite understand yet.*/
-                        pen.DashPattern = this.StrokeDashArray.ConvertAll(u => u.Value/((strokeWidth <= 0) ? 1 : strokeWidth)).ToArray();
+                        pen.DashPattern = this.StrokeDashArray.ConvertAll(u => ((u.Value <= 0) ? 1 : u.Value) / ((strokeWidth <= 0) ? 1 : strokeWidth)).ToArray();
                     }
 
                     renderer.DrawPath(pen, this.Path);
@@ -247,4 +247,4 @@ namespace Svg
         }
 
     }
-}
\ No newline at end of file
+}