Bitcoin-Qt: Use qDebug() for printing to debug.log

- removes all usages of PrintDebugStringF from Qt code
- ensure same format for all debug.log messages "functionname : Message"

src/qt/clientmodel.h

@@ -60,8 +60,8 @@ private:
 
     int cachedNumBlocks;
     int cachedNumBlocksOfPeers;
-	bool cachedReindexing;
-	bool cachedImporting;
+    bool cachedReindexing;
+    bool cachedImporting;
 
     int numBlocksAtStartup;