(NDK) Added Listener component and system

Former-commit-id: 0553c4ad9a7e33608e9ab91bd4ca8812272a6293

SDK/src/NDK/World.cpp

@@ -4,6 +4,7 @@
 
 #include <NDK/World.hpp>
 #include <Nazara/Core/Error.hpp>
+#include <NDK/Systems/ListenerSystem.hpp>
 
 namespace Ndk
 {
@@ -13,6 +14,11 @@ namespace Ndk
 		Clear();
 	}
 
+	void World::AddDefaultSystems()
+	{
+		AddSystem<ListenerSystem>();
+	}
+
 	const EntityHandle& World::CreateEntity()
 	{
 		EntityId id;