Remove obsolete Node::setTransformChangedCallback()

This callback mechanism seems to have only been used by the now-removed light
list system.

libs/scene/Node.cpp

@@ -440,11 +440,6 @@ void Node::transformChangedLocal()
 	_transformMutex = false;
 	_boundsChanged = true;
 	_childBoundsChanged = true;
-
-	if (_transformChangedCallback)
-	{
-		_transformChangedCallback();
-	}
 }
 
 void Node::transformChanged()
@@ -462,10 +457,6 @@ void Node::transformChanged()
 	boundsChanged();
 }
 
-void Node::setTransformChangedCallback(const Callback& callback) {
-	_transformChangedCallback = callback;
-}
-
 RenderSystemPtr Node::getRenderSystem() const
 {
 	return _renderSystem.lock();

libs/scene/Node.h

@@ -50,7 +50,6 @@ class Node :
 	mutable bool _childBoundsMutex;
 	mutable bool _transformChanged;
 	mutable bool _transformMutex;
-	Callback _transformChangedCallback;
 
 	mutable Matrix4 _local2world;
 
@@ -152,8 +151,6 @@ class Node :
 
 	void transformChanged() override;
 
-	void setTransformChangedCallback(const Callback& callback);
-
 	// greebo: This gets called as soon as a scene::Node gets inserted into
 	// the TraversableNodeSet. This triggers an instantiation call on the child node.
 	virtual void onChildAdded(const INodePtr& child);