Mark where we'd create and leave scope for a scoped_renderer ctx that auto-flushes on delete without cleaning out underlying buffers.

This work will occur in the {game} tool under TDD.

src/level.cxx

@@ -140,6 +140,7 @@ void level::update_waves(float delta) {
 }
 
 void level::render() {
+  // Open Scope
   renderer().draw(player_->render_info());
   for (auto & a : actors_) {
     renderer().draw(a->render_info());
@@ -147,5 +148,5 @@ void level::render() {
   for (auto & b : bullets_) {
     renderer().draw(b->render_info());
   }
-  renderer().flush();
+  renderer().flush(); // Exit Scope
 }