refs #270 don't call CRuntime::gracefulShutdown from a different thread;

connect it to the QCoreApplication::aboutToQuit signal instead

samples/blackcore/tool.cpp

@@ -154,7 +154,6 @@ namespace BlackMiscTest
                 else if (line.startsWith("all")) runtime->slotLog(enable);
             }
         }
-        runtime->gracefulShutdown();
         QCoreApplication::quit();
     }
 } // namespace