QML Observer: Refresh debug id's when new objects are created

Previously, the user had to navigate to the context of a qml item in
order to edit its source code in Live Preview mode. This change tells
the client to update when new objects are created on server-side, and
makes the editing possible without having to manually trigger updates.

src/plugins/qmljsinspector/qmljsdesigndebugclient.h

@@ -89,6 +89,7 @@ signals:
     void designModeBehaviorChanged(bool inDesignMode);
     void reloaded(); // the server has reloaded the document
     void contextPathUpdated(const QStringList &path);
+    void treeRefreshRequested(); // scene has some new items
 
 protected:
     virtual void messageReceived(const QByteArray &);