added basic functions to collect bandwidth info in pqistreamer both ways; added a sorting method in BWGraphSource to create curves from extracted BW info. Still not yet functional

git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@8600 b45a01b8-16f6-495d-af2f-9b41ad6348cc

retroshare-gui/src/gui/common/RSGraphWidget.h

@@ -89,7 +89,7 @@ public:
 protected slots:
     // Calls the internal source for a new data points; called by the timer. You might want to overload this
     // if the collection system needs it. Otherwise, the default method will call getValues()
-    void update() ;
+    virtual void update() ;
 	 void updateIfPossible() ;
 
 protected: