Added a Initialize function for systems.

include/Engine/Core/System.h

@@ -15,10 +15,10 @@ public:
         , m_ComponentType(componentType)
     { }
 	
-	virtual void Initialize();
+	virtual void Initialize() { }
     virtual void Update(World* world, ComponentWrapper& component, double dt) = 0;
 
-private:
+protected:
     std::string m_ComponentType;
 	EventBroker* m_EventBroker;
 };

include/Engine/Core/SystemPipeline.h

@@ -21,6 +21,16 @@ public:
         }
     }
 
+	void Initialize()
+	{
+		for (auto& pair : m_Systems) {
+			auto& systems = pair.second;
+			for (auto& system : systems) {
+				system->Initialize();
+			}
+		}
+	}
+
     template <typename T, typename... Arguments>
     void AddSystem(Arguments... args)
     {