If changed settings require a restart, offer the user to do it now.

Add a dialog when closing the settings screen asking the user if they would like to restart the game now in order to apply any settings that are only applied after restarting the game. The game is reloaded in-process by spinning up a new AppDomain in order to reset state.

OpenRA.Renderer.Sdl2/Sdl2Input.cs

@@ -170,9 +170,7 @@ namespace OpenRA.Renderer.Sdl2
 						// Special case workaround for windows users
 						if (e.key.keysym.sym == SDL.SDL_Keycode.SDLK_F4 && mods.HasModifier(Modifiers.Alt) &&
 							Platform.CurrentPlatform == PlatformType.Windows)
-						{
 							Game.Exit();
-						}
 						else
 							inputHandler.OnKeyInput(keyEvent);