Ensure monitor mode is enabled when tune button clicked.

Monitor mode  was not  being enabled when  clicking the  "Tune" button
which could mean that neither split  mode nor the correct TX frequency
were being set.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@4270 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

mainwindow.cpp

@@ -2640,6 +2640,7 @@ void MainWindow::on_tuneButton_clicked (bool checked)
     {
       m_sent73=false;
       m_repeatMsg=0;
+      on_monitorButton_clicked (true);
     }
   m_tune = checked;
   Q_EMIT tune (checked);