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/ui/qdarkstyle/style.qss

@@ -1831,6 +1831,7 @@ QColumnView:selected {
   color: #32414B;
 }
 
+
 QTreeView:hover,
 QListView:hover,
 QTableView:hover,
@@ -1838,6 +1839,7 @@ QColumnView:hover {
   background-color: #19232D;
 }
 
+
 QTreeView::item:pressed,
 QListView::item:pressed,
 QTableView::item:pressed,