Initial CEF and DirectX overlay implementation (PoC, unfinished)

Still pretty unstable, game might crash at times.
Revamp build system and other small fixes

Client/Scripts/GUI/CefClient.cs

@@ -0,0 +1,112 @@
+using System;
+using System.Drawing;
+using DXHook.Hook.Common;
+using GTA;
+using RageCoop.Client.CefHost;
+using RageCoop.Client.Scripting;
+
+namespace RageCoop.Client.GUI
+{
+    public class CefClient
+    {
+        public readonly int Id;
+        internal CefAdapter Adapter;
+        internal CefController Controller;
+        internal ImageElement MainFrame;
+
+        internal CefClient(int id, Size size)
+        {
+            Id = id;
+            Controller = CefController.Create(id, size, out Adapter, BufferMode.Full);
+            MainFrame = new ImageElement(size.Width, size.Height, 4, Adapter.PtrBuffer);
+            Adapter.OnPaint += (len, dirty) =>
+            {
+                try
+                {
+                    // Image is using same shared buffer, so just need to make it re-copied to GPU
+                    MainFrame.Invalidate();
+                }
+                catch (Exception ex)
+                {
+                    API.Logger.Error(ex);
+                }
+            };
+        }
+
+        internal void Destroy()
+        {
+            Controller.Dispose();
+            Adapter.Dispose();
+            MainFrame.Dispose();
+        }
+
+        public Point GetLocationInFrame(Point screenPos)
+        {
+            screenPos.X -= MainFrame.Location.X;
+            screenPos.Y -= MainFrame.Location.Y;
+            return screenPos;
+        }
+
+        public Point GetLocationInCef(Point screenPos)
+        {
+            var p = GetLocationInFrame(screenPos);
+            p.X = (int)(p.X / Scale);
+            p.Y = (int)(p.Y / Scale);
+            return p;
+        }
+
+        internal bool PointInArea(Point screen)
+        {
+            screen = GetLocationInFrame(screen);
+            return screen.X.IsBetween(0, Width) && screen.Y.IsBetween(0, Height);
+        }
+
+        internal void Tick()
+        {
+            var mousePos = Util.CursorPosition;
+            if (!PointInArea(mousePos)) return;
+            var pos = GetLocationInCef(mousePos);
+            if (Game.IsControlJustPressed(Control.CursorAccept))
+                Controller.SendMouseClick(pos.X, pos.Y, 0, MouseButton.Left, false, 1);
+            else if (Game.IsControlJustReleased(Control.CursorAccept))
+                Controller.SendMouseClick(pos.X, pos.Y, 0, MouseButton.Left, true, 1);
+        }
+
+        #region FRAME-APPERANCE
+
+        public float Scale
+        {
+            get => MainFrame.Scale;
+            set => MainFrame.Scale = value;
+        }
+
+        public Color Tint
+        {
+            get => MainFrame.Tint;
+            set => MainFrame.Tint = value;
+        }
+
+        public byte Opacity
+        {
+            get => MainFrame.Opacity;
+            set => MainFrame.Opacity = value;
+        }
+
+        public Point Location
+        {
+            get => MainFrame.Location;
+            set => MainFrame.Location = value;
+        }
+
+        public int Width => MainFrame.Width;
+        public int Height => MainFrame.Height;
+
+        public bool Hidden
+        {
+            get => MainFrame.Hidden;
+            set => MainFrame.Hidden = value;
+        }
+
+        #endregion
+    }
+}