Improved graceful shutdown, added "m_shutdownInProgress"

* no assert when wait is called in same thread, just ignore wait
* quitAndWait readers, also works if not already noved in new thread (see above)

src/blackcore/db/networkwatchdog.cpp

@@ -207,6 +207,7 @@ namespace BlackCore
         void CNetworkWatchdog::gracefulShutdown()
         {
             this->pingDbClientService(PingCompleteShutdown);
+            this->quit();
         }
 
         void CNetworkWatchdog::pingDbClientService(CNetworkWatchdog::PingType type, bool force)