Ref T536, overlay text messages

* signals for text message requests
* frame for overlay plus CEnableForDockWidgetInfoArea
* correctly init inner frame size

src/blackgui/overlaymessages.h

@@ -75,6 +75,9 @@ namespace BlackGui
         //! Active send/receive of text messages
         void activateTextMessages(bool activate);
 
+        //! Are text messages
+        bool isTextMessagesActivated() const;
+
         //! Display image
         void setModeToImage();