Add SuppressedProperty Visible

[tznind]

Adds the concept of 'Suppressed' properties. These manifest only in the code generated but are not visible in the editor (i.e. property is not set on the View that is hosted in the main editing window).

This is consistent with the behaviour of e.g. the WinForms editor when handling properties such as Visible. The user should be able to see from the property info that the view is not visible but it should remain clickable, draggable etc in the editor.

//------------------------------------------------------------------------------

//  <auto-generated>
//      This code was generated by:
//        TerminalGuiDesigner v1.0.24.0
//      Changes to this file may cause incorrect behavior and will be lost if
//      the code is regenerated.
//  </auto-generated>
// -----------------------------------------------------------------------------
namespace YourNamespace {
    using System;
    using Terminal.Gui;

    public partial class MyView : Terminal.Gui.Window {

        private Terminal.Gui.Button button;

        private void InitializeComponent() {
            this.button = new Terminal.Gui.Button();
            this.Width = Dim.Fill(0);
            this.Height = Dim.Fill(0);
            this.X = 0;
            this.Y = 0;
+           this.Visible = true;
            this.Modal = false;
            this.Border.BorderStyle = Terminal.Gui.BorderStyle.Single;
            this.Border.BorderBrush = Terminal.Gui.Color.White;
            this.Border.Effect3D = false;
            this.Border.Effect3DBrush = null;
            this.Border.DrawMarginFrame = true;
            this.TextAlignment = Terminal.Gui.TextAlignment.Left;
            this.Title = "";
            this.button.Width = 24;
            this.button.Height = 1;
            this.button.X = 11;
            this.button.Y = 4;
+           this.button.Visible = false;
            this.button.Data = "button";
            this.button.Text = "I will be invisible!";
            this.button.TextAlignment = Terminal.Gui.TextAlignment.Centered;
            this.button.IsDefault = false;
            this.Add(this.button);
        }
    }
}