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/KRVector3.cpp

@@ -32,6 +32,7 @@
 #include "KRVector3.h"
 
 #include <math.h>
+#include <limits.h>
 
 //default constructor
 KRVector3::KRVector3()
@@ -47,6 +48,14 @@ KRVector3::KRVector3(const KRVector3 &v) {
     z = v.z;
 }
 
+KRVector3 KRVector3::Min() {
+    return KRVector3(-std::numeric_limits<float>::max());
+}
+
+KRVector3 KRVector3::Max() {
+    return KRVector3(std::numeric_limits<float>::max());
+}
+
 KRVector3 KRVector3::Zero() {
     return KRVector3(0.0f, 0.0f, 0.0f);
 }