Adding SpringMobilityModel to adjust positions of nodes in large
topologies

Inspired by http://en.wikipedia.org/wiki/Force-based_algorithms_%28graph_drawing%29
diff --git a/model/rocketfuel-weights-reader.h b/model/rocketfuel-weights-reader.h
index 2b73c11..ecf4905 100644
--- a/model/rocketfuel-weights-reader.h
+++ b/model/rocketfuel-weights-reader.h
@@ -39,7 +39,7 @@
 class RocketfuelWeightsReader : public AnnotatedTopologyReader
 {
 public:
-  RocketfuelWeightsReader ();
+  RocketfuelWeightsReader (const std::string &path="");
   virtual ~RocketfuelWeightsReader ();
 
   void
@@ -55,7 +55,11 @@
    *
    * \return the container of the nodes created (or empty container if there was an error)
    */
-  virtual NodeContainer Read (void);
+  virtual NodeContainer 
+  Read (void);
+
+  void
+  Commit ();
 
   enum
     {
@@ -63,6 +67,9 @@
       LATENCIES
     };
 
+  // void
+  // Cheat (NodeContainer &nodes);
+
 private:
   RocketfuelWeightsReader (const RocketfuelWeightsReader&);
   RocketfuelWeightsReader& operator= (const RocketfuelWeightsReader&);