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/annotated-topology-reader.h b/model/annotated-topology-reader.h
index cbcd890..b9268b8 100644
--- a/model/annotated-topology-reader.h
+++ b/model/annotated-topology-reader.h
@@ -53,8 +53,14 @@
    *
    * \return the container of the nodes created (or empty container if there was an error)
    */
-  virtual
-  NodeContainer Read (void);
+  virtual NodeContainer
+  Read ();
+
+  /**
+   * \brief Get nodes read by the reader
+   */
+  NodeContainer
+  GetNodes () const;
     
   /**
    * \brief Assign IPv4 addresses to all links
@@ -92,6 +98,7 @@
     
 protected:
   std::string m_path;
+  NodeContainer m_nodes;
 
 private:
   AnnotatedTopologyReader (const AnnotatedTopologyReader&);