[GNOME] Menu Bar

Issue generated from Tuleap's migration script. Originally submitted by: Óvári (ovari)

 1. Please implement a Menu Bar  

 2. The top level menu items could be: File, Edit, View, Contacts, Conversations, Call, Tools, Help  

 3. It will enable keyboard accelerators to be added for keyboard use (should there be no mouse, or the mouse does not work).  

 4. Items in the Menu and Settings buttons should be moved to the Menu Bar.  

 5. Please advise if you require any additional information.  

 6. Please advise when this feature has been implemented for testing purposes.

Thank you