Modifying SpringMobilityModel to make all nodes readjust after even one
node changes its position (previously only this node was adjusting itself)

SpringMobilityModel now updates positions based on internal (static) timer
diff --git a/model/rocketfuel-weights-reader.h b/model/rocketfuel-weights-reader.h
index ecf4905..cf6a784 100644
--- a/model/rocketfuel-weights-reader.h
+++ b/model/rocketfuel-weights-reader.h
@@ -64,12 +64,13 @@
   enum
     {
       WEIGHTS,
-      LATENCIES
+      LATENCIES,
+      POSITIONS
     };
 
-  // void
-  // Cheat (NodeContainer &nodes);
-
+  void
+  SavePositions (const std::string &file) const;
+  
 private:
   RocketfuelWeightsReader (const RocketfuelWeightsReader&);
   RocketfuelWeightsReader& operator= (const RocketfuelWeightsReader&);