Implemented KROctree class to be used by upcoming occlusion culling and physics features

Refactored scene graph notification system structures to be owned by the KRScene object
Merged Mike's changes

--HG--
extra : convert_revision : svn%3A7752d6cf-9f14-4ad2-affc-04f1e67b81a5/trunk%4082

KREngine/KREngine/Classes/KROctree.h

@@ -0,0 +1,33 @@
+//
+//  KROctree.h
+//  KREngine
+//
+//  Created by Kearwood Gilbert on 2012-08-29.
+//  Copyright (c) 2012 Kearwood Software. All rights reserved.
+//
+
+#ifndef KRAABBTREE_H
+#define KRAABBTREE_H
+
+#import "KREngine-common.h"
+#include "KROctreeNode.h"
+
+class KRNode;
+
+class KROctree {
+public:
+    KROctree();
+    ~KROctree();
+    
+    void add(KRNode *pNode);
+    void remove(KRNode *pNode);
+    void update(KRNode *pNode);
+    
+private:
+    KROctreeNode *m_pRootNode;
+    std::set<KRNode *>m_outerSceneNodes;
+    
+    void shrink();
+};
+
+#endif /* defined(KRAABBTREE_H) */