make buttons in mode panel act like radiobuttons

apps/opencs/view/widget/pushbutton.cpp

@@ -21,6 +21,7 @@ void CSVWidget::PushButton::mouseReleaseEvent (QMouseEvent *event)
 CSVWidget::PushButton::PushButton (const QIcon& icon, const QString& text, QWidget *parent)
 : QPushButton (icon, text, parent), mKeepOpen (false)
 {
+    setCheckable (true);
 }
 
 bool CSVWidget::PushButton::hasKeepOpen() const

apps/opencs/view/widget/scenetoolmode.cpp

@@ -40,7 +40,10 @@ void CSVWidget::SceneToolMode::addButton (const std::string& icon, const std::st
     connect (button, SIGNAL (clicked()), this, SLOT (selected()));
 
     if (mButtons.size()==1)
+    {
         setIcon (button->icon());
+        button->setChecked (true);
+    }
 }
 
 void CSVWidget::SceneToolMode::selected()
@@ -53,6 +56,10 @@ void CSVWidget::SceneToolMode::selected()
         if (!iter->first->hasKeepOpen())
             mPanel->hide();
 
+        for (std::map<PushButton *, std::string>::const_iterator iter2 = mButtons.begin();
+            iter2!=mButtons.end(); ++iter2)
+            iter2->first->setChecked (iter2==iter);
+
         setIcon (iter->first->icon());
         emit modeChanged (iter->second);
     }