fixed invisible output view in VECTO3GUI2020

VECTO3GUI2020/Views/OutputView.xaml.cs

-namespace VECTO3GUI2020.Views
+using System.Windows.Controls;
+
+namespace VECTO3GUI2020.Views
 {
     /// <summary>
     /// Interaction logic for OutputView.xaml
     /// </summary>
-    public partial class OutputView
+    public partial class OutputView : UserControl
     {
-	}
+		public OutputView()
+		{
+			InitializeComponent();
+		}
+    }
 }