remove all async_start/end calls

src/node.cpp

@@ -42,21 +42,6 @@ void Node::app_redraw()
     App::I.redraw = true;
 }
 
-void Node::async_start()
-{
-    App::I.async_start();
-}
-
-void Node::async_update()
-{
-    App::I.async_update();
-}
-
-void Node::async_end()
-{
-    App::I.async_end();
-}
-
 void Node::watch(std::function<bool(Node*)> observer)
 {
     bool cont = observer(this);