shutdown based on platform, update accessors for editors

src/app/editor/master_editor.cc

@@ -87,8 +87,6 @@ absl::Status MasterEditor::Update() {
 
   ManageActiveEditors();
 
-  End();
-
   return absl::OkStatus();
 }
 

src/app/editor/master_editor.h

@@ -75,6 +75,7 @@ class MasterEditor : public SharedRom,
 
   auto emulator() -> emu::Emulator& { return emulator_; }
   auto quit() { return quit_; }
+  auto overworld_editor() -> OverworldEditor& { return overworld_editor_; }
 
  private:
   void ManageActiveEditors();