added clicked event to gui button

Source/MonoGame.Extended/Gui/GuiButton.cs

@@ -1,3 +1,4 @@
+using System;
 using Microsoft.Xna.Framework;
 using Microsoft.Xna.Framework.Input;
 
@@ -21,6 +22,8 @@ namespace MonoGame.Extended.Gui
         public bool IsPressed { get; private set; }
         public bool IsHovered { get; private set; }
 
+        public event EventHandler Clicked;
+
         public override GuiControlStyle CurrentStyle
         {
             get
@@ -38,9 +41,13 @@ namespace MonoGame.Extended.Gui
         public override void Update(GameTime gameTime)
         {
             var mouseState = Mouse.GetState();
+            var previouslyPressed = IsPressed;
 
             IsHovered = Shape.Contains(mouseState.X, mouseState.Y);
             IsPressed = IsHovered && mouseState.LeftButton == ButtonState.Pressed;
+
+            if(previouslyPressed && !IsPressed && IsHovered)
+                Clicked.Raise(this, EventArgs.Empty);
         }
     }
 }

Source/SpaceGame/GameMain.cs

@@ -66,6 +66,10 @@ namespace SpaceGame
             {
                 Position = new Vector2(400, 370)
             };
+            button.Clicked += (sender, args) =>
+            {
+                _player.Destroy();
+            };
             _guiManager.Layout.Controls.Add(button);