Add native restart menu button

It should replace Simply Love restart hack.
Now it is possible to assign any button to restart.

src/ScreenEvaluation.cpp

@@ -729,6 +729,13 @@ bool ScreenEvaluation::Input( const InputEventPlus &input )
 	if( IsTransitioning() )
 		return false;
 
+	if (input.MenuI == GAME_BUTTON_RESTART && input.type == IET_FIRST_PRESS &&
+		GAMESTATE->IsEventMode() && !GAMESTATE->IsCourseMode())
+	{
+		return MenuRestart(input);
+	}
+
+
 	if( input.GameI.IsValid() )
 	{
 		if( CodeDetector::EnteredCode(input.GameI.controller, CODE_SAVE_SCREENSHOT1) ||
@@ -795,6 +802,16 @@ bool ScreenEvaluation::MenuStart( const InputEventPlus &input )
 	return true;
 }
 
+bool ScreenEvaluation::MenuRestart( const InputEventPlus &input )
+{
+	if( IsTransitioning() )
+		return false;
+
+	SCREENMAN->GetTopScreen()->SetNextScreenName("ScreenGameplay");
+	StartTransitioningScreen( SM_GoToNextScreen );
+	return true;
+}
+
 void ScreenEvaluation::HandleMenuStart()
 {
 	StartTransitioningScreen( SM_GoToNextScreen );