Add sync group number to the timeline title bar and/or window browser tree

[mjbsc]

It would be useful to see the sync group of a window without having to right click and hover over the Synchronize menu item, like having it in the timeline window title bar and/or in the window browser. I did a PoC for the title bar (see below) and seems to work fine, but I'm not sure which place would be better.

At src/gtimeline.cpp:1623

   string composedName = myWindow->getName() + " @ " +
                         myWindow->getTrace()->getTraceNameNumbered();
 
+  if (myWindow->isSync()) {
+    composedName = to_string(myWindow->getSyncGroup() + 1) + " - " + composedName;
+  }
+
   this->SetTitle( wxString::FromUTF8( composedName.c_str() ) );

[executre]

Thanks for the suggestion!
We will try to integrate your code in a new function that could be used from main window in order to show the same name in the window browser.