New Components/ Prepare to new scene loading system

entitysystem/ECSPersistence.h

@@ -0,0 +1,12 @@
+#pragma once
+#include <string>
+
+class ECWorld;
+
+namespace ecs_persistence
+{
+    // Save all named entities to a JSON file. Returns number of entities saved, or -1 on error.
+    int save(ECWorld &world, const std::string &path);
+    // Load entities from a JSON file. Skips entities whose name already exists. Returns count loaded, or -1 on error.
+    int load(ECWorld &world, const std::string &path);
+}