Misc networking fixes

- connecting to nodes is much faster and more reliable now
- reduced the amount of spaghetti in libwalletqt and greatly simplified the logic in nodes.cpp
- Settings -> Node dialog should feel slightly more responsive
- during synchronization the status bar will now display the amount of data downloaded
- fixed some edge cases that could cause unreasonably long hangs
- Help -> Debug Info screen now auto-updates every 5 seconds
- Don't use SSL over Tor

src/utils/utils.h

@@ -95,6 +95,8 @@ public:
     static bool pixmapWrite(const QString &path, const QPixmap &pixmap);
     static QFont relativeFont(int delta);
     static double roundSignificant(double N, double n);
+    static QString formatBytes(quint64 bytes);
+
     static QStringList randomHTTPAgents;
 
     template<typename QEnum>