Deleted demo.cs; changed to Example.cs from README

Example/Example.cs

@@ -0,0 +1,76 @@
+// A simple Terminal.Gui example in C# - using C# 9.0 Top-level statements
+// This is the same code found in the Termiminal Gui README.md file.
+
+using Terminal.Gui;
+using NStack;
+
+Application.Init ();
+
+// Creates the top-level window to show
+var win = new Window ("Example App") {
+	X = 0,
+	Y = 1, // Leave one row for the toplevel menu
+
+	// By using Dim.Fill(), this Window will automatically resize without manual intervention
+	Width = Dim.Fill (),
+	Height = Dim.Fill ()
+};
+
+Application.Top.Add (win);
+
+// Creates a menubar, the item "New" has a help menu.
+var menu = new MenuBar (new MenuBarItem [] {
+			new MenuBarItem ("_File", new MenuItem [] {
+				new MenuItem ("_New", "Creates a new file", null),
+				new MenuItem ("_Close", "",null),
+				new MenuItem ("_Quit", "", () => { if (Quit ()) Application.Top.Running = false; })
+			}),
+			new MenuBarItem ("_Edit", new MenuItem [] {
+				new MenuItem ("_Copy", "", null),
+				new MenuItem ("C_ut", "", null),
+				new MenuItem ("_Paste", "", null)
+			})
+		});
+Application.Top.Add (menu);
+
+static bool Quit ()
+{
+	var n = MessageBox.Query (50, 7, "Quit Example", "Are you sure you want to quit this example?", "Yes", "No");
+	return n == 0;
+}
+
+var login = new Label ("Login: ") { X = 3, Y = 2 };
+var password = new Label ("Password: ") {
+	X = Pos.Left (login),
+	Y = Pos.Top (login) + 1
+};
+var loginText = new TextField ("") {
+	X = Pos.Right (password),
+	Y = Pos.Top (login),
+	Width = 40
+};
+var passText = new TextField ("") {
+	Secret = true,
+	X = Pos.Left (loginText),
+	Y = Pos.Top (password),
+	Width = Dim.Width (loginText)
+};
+
+// Add the views to the main window, 
+win.Add (
+	// Using Computed Layout:
+	login, password, loginText, passText,
+
+	// Using Absolute Layout:
+	new CheckBox (3, 6, "Remember me"),
+	new RadioGroup (3, 8, new ustring [] { "_Personal", "_Company" }, 0),
+	new Button (3, 14, "Ok"),
+	new Button (10, 14, "Cancel"),
+	new Label (3, 18, "Press F9 or ESC plus 9 to activate the menubar")
+);
+
+// Run blocks until the user quits the application
+Application.Run ();
+
+// Always bracket Application.Init with .Shutdown.
+Application.Shutdown ();