remove shutdown

src/app/core/controller.cc

@@ -260,7 +260,6 @@ void Controller::DoRender() const {
 }
 
 void Controller::OnExit() {
-  master_editor_.Shutdown();
   if (flags()->kLoadAudioDevice) {
     SDL_PauseAudioDevice(audio_device_, 1);
     SDL_CloseAudioDevice(audio_device_);

src/app/editor/master_editor.h

@@ -62,8 +62,6 @@ class MasterEditor : public SharedRom,
                    std::string filename = "");
   absl::Status Update();
 
-  void Shutdown() { overworld_editor_.Shutdown(); }
-
   auto emulator() -> emu::Emulator& { return emulator_; }
   auto quit() { return quit_; }
 

src/app/editor/overworld_editor.h

@@ -102,25 +102,6 @@ class OverworldEditor : public Editor,
   int jump_to_tab() { return jump_to_tab_; }
   int jump_to_tab_ = -1;
 
-  void Shutdown() {
-    for (auto& bmp : tile16_individual_) {
-      bmp.Cleanup();
-    }
-    for (auto& [i, bmp] : maps_bmp_) {
-      bmp.Cleanup();
-    }
-    for (auto& [i, bmp] : graphics_bin_) {
-      bmp.Cleanup();
-    }
-    for (auto& [i, bmp] : current_graphics_set_) {
-      bmp.Cleanup();
-    }
-    maps_bmp_.clear();
-    overworld_.Destroy();
-    all_gfx_loaded_ = false;
-    map_blockset_loaded_ = false;
-  }
-
   /**
    * @brief Load the Bitmap objects for each OverworldMap.
    *