Object transfers and cleaning

[JonathSpirit]

Changes Overview:

Object Class:

• Modified first() and removed() methods to take a reference to a Scene instead of a pointer, ensuring the Scene cannot be null.
• Introduced a new virtual method transfered().
• Updated update() method to use a reference instead of a pointer.
• Added helper update() methods that do not require a Scene parameter, utilizing _myObjectData.
• Added a virtual method netSignaled() for network signaling.

Scene Class:

• Modified transferObject() to utilize Object::transfered().
• Fixed transferObject() to return the object pointer correctly.
• Replaced pointers with references for callback methods.
• Added OBJECT_SIGNALED network event and signalObject() method.
• Cleaned up SceneNetEvent.

These changes improve the robustness and readability of the Object and Scene classes by removing null pointer possibilities and streamlining event handling.