Add SDL2 renderer based on SDL2# wrapper. Closes #3315.

SDL2# binary was built from commit 70af91f84493a924a3c1da46ae6209bb5f7222e3.

OpenRA.Renderer.Gl/GraphicsDevice.cs

@@ -39,6 +39,6 @@ namespace OpenRA.Renderer.Glsl
 		public GraphicsDevice(Size size, WindowMode window)
 			: base(size, window, requiredExtensions) { }
 
-		public override IShader CreateShader(string name) { return new Shader(this, name); }
+		public override IShader CreateShader(string name) { return new Shader(name); }
 	}
 }