Fix null case.

src/fr/devinsy/xidyn/presenters/URLPresenter.java

@@ -94,7 +94,27 @@ public class URLPresenter extends StringPresenter
 	{
 		String result;
 
-		result = this.source.toString();
+		if (this.source == null)
+		{
+			result = null;
+		}
+		else
+		{
+			result = this.source.toString();
+		}
+
+		//
+		return (result);
+	}
+
+	/**
+	 *
+	 */
+	public URL getURL()
+	{
+		URL result;
+
+		result = this.source;
 
 		//
 		return (result);