Add GetWorld to Actor. Integrate google test. Add Model manager class. Rename *.h to *.hpp files

Core/Game/World/World.cpp

@@ -1,6 +1,6 @@
-#include "World.h"
+#include "World.hpp"
 
-#include "Game/SaveMap/SaveMap.h"
+#include "Game/SaveMap/SaveMap.hpp"
 
 World::World(GameInstance& game_instance) : game_instance(game_instance)
 {
@@ -35,4 +35,7 @@ std::shared_ptr<SaveMap> World::save()
 void World::load(std::shared_ptr<SaveMap> save)
 {
     actors = std::move(reinterpret_cast<std::list<Actor*>&>(save->GetListObject("Actors")));
+
+    for (auto& i : actors)
+        i->world_ = this;
 }