fix borderless window not minimizable from taskbar

Changelog.md

@@ -11,6 +11,10 @@
 - in the learn window of the input editor support was added for
   mouse left, mouse left double, mouse mid, mouse forward, mouse back
 - libmpv updated to shinchiro 2019-07-07
+- when border is none it wasn't possible to minimize the window from
+  the task bar because this is the WinForms default behavier. This
+  was fixed by calling Spy++ to the rescue and adding WS_MINIMIZEBOX
+  in CreateParams  
 
 ### 4.6
 

mpv.net/WinForms/MainForm.cs

@@ -350,6 +350,14 @@ namespace mpvnet
            Msg.ShowError(e.ExceptionObject.ToString());
         }
 
+        protected override CreateParams CreateParams {
+            get {
+                CreateParams cp = base.CreateParams;
+                cp.Style |= 0x00020000 /* WS_MINIMIZEBOX */;
+                return cp;
+            }
+        }
+
         protected override void WndProc(ref Message m)
         {
             //System.Diagnostics.Debug.WriteLine(m);