More hints

For serial ports which look like PM3 hardware, show a '*' behind them.
Show message box if the GUI fails to connect to the hardware

src/common/pm3process.cpp

@@ -61,7 +61,10 @@ void PM3Process::connectPM3(const QString& path, const QStringList args)
             emit PM3StatedChanged(true, result);
         }
         else
+        {
+            emit HWConnectFailed();
             kill();
+        }
     }
 
     setRequiringOutput(false);

src/common/pm3process.h

@@ -48,6 +48,7 @@ signals:
     void PM3StatedChanged(bool st, const QString& info = "");
     void newOutput(const QString& output);
     void changeClientType(Util::ClientType);
+    void HWConnectFailed();
 };
 
 #endif // PM3PROCESS_H