Added DEF events for unity toggle and desktop panel draw.

Also this is the first REAL AppVeyor build test.

source/WindowsFormsApplication1/API.cs

@@ -83,6 +83,8 @@ public class ModApplauncherItem
     public class API
     {
         public static Dictionary<Form, string> OpenGUIDs = new Dictionary<Form, string>();
+        public static Dictionary<string, Control> DEF_PanelGUIDs = new Dictionary<string, Control>();
+
 
         /// <summary>
         /// Settings file.

source/WindowsFormsApplication1/Desktop/ShiftOSDesktop.cs

@@ -32,6 +32,9 @@ public ShiftOSDesktop()
         //Window draw event handler.
         public delegate void WindowDrawEventHandler(Form win);
 
+        //Event handler for passing a single control (e.g, a desktop panel) to the Lua API.
+        public delegate void ControlDrawEventHandler(string ControlGUID);
+
         //Lua events.
         public event EmptyEventHandler OnDesktopReload;
         public event ListEventHandler<ApplauncherItem> OnAppLauncherPopulate;
@@ -45,6 +48,8 @@ public ShiftOSDesktop()
         public event WindowDrawEventHandler TitlebarReset;
         public event WindowDrawEventHandler BorderReset;
         public event ListEventHandler<DesktopIcon> DesktopIconsPopulated;
+        public event EmptyEventHandler OnUnityToggle;
+        public event ControlDrawEventHandler OnDesktopPanelDraw;
 
         public void InvokeWindowOp(string operation, Form win)
         {
@@ -104,7 +109,9 @@ public void SetUnityMode()
             {
                 UnityEnabled = true;
             }
+            OnUnityToggle?.Invoke(); //We want this to be invoked BEFORE the desktop reset in case the user wants to do things with the desktop during reset.
             SetupDesktop();
+            
         }
 
         public void SetUnityMode(bool value)
@@ -596,7 +603,7 @@ public void SetupDesktopPanel()
         public void SetupPanels(List<Skinning.DesktopPanel> lst)
         {
             DesktopPanels = new List<Panel>();
-
+            API.DEF_PanelGUIDs.Clear();
             foreach (var dp in lst)
             {
                 Panel pnl = new Panel();
@@ -699,6 +706,9 @@ public void SetupPanels(List<Skinning.DesktopPanel> lst)
                     pnl.Hide();
                     this.Controls.Remove(pnl);
                 }
+                string guid = Guid.NewGuid().ToString();
+                API.DEF_PanelGUIDs.Add(guid, pnl);
+                OnDesktopPanelDraw?.Invoke(guid);
             }
 
         }

source/WindowsFormsApplication1/Engine/Lua_Interp.cs

@@ -119,6 +119,30 @@ public void RegisterCore()
                     mod(func + "()");
                 };
             });
+            mod.on_unity_set += new Action<ShiftOSDesktop, string>((desktop, func) =>
+            {
+                desktop.OnUnityToggle += () =>
+                {
+                    mod(func + "()");
+                };
+            });
+            mod.on_desktop_panel_draw += new Action<ShiftOSDesktop, string>((desktop, func) =>
+            {
+                desktop.OnDesktopPanelDraw += (c) =>
+                {
+                    mod(func + $"(get_panel_from_guid(\"{c}\"))");
+                };
+            });
+            mod.get_panel_from_guid = new Func<string, Control>((guid) =>
+            {
+                foreach(var kv in API.DEF_PanelGUIDs)
+                {
+                    if (kv.Key == guid)
+                        return kv.Value;
+                }
+                return null;
+            });
+
             mod.on_desktop_reset += new Action<ShiftOSDesktop, string>((desktop, func) =>
             {
                 desktop.OnDesktopReload += () =>