Fixed issue with clicking on PM bubbles

Previously would not open the client if the window was minimized.
Added the same popup fix for mentions

cockatrice/src/tab_message.h

@@ -25,6 +25,7 @@ private:
     QAction *aLeave;
 signals:
     void talkClosing(TabMessage *tab);
+    void maximizeClient();
 private slots:
     void sendMessage();
     void actLeave();