e17: add option to have gadcon client settings menu in toplevel again.

e17: add option to have gadcon client settings menu in toplevel again.

added e_menu_item_new_relative(E_Menu, E_Menu_Item *rel) which appends
 new item to rel or prepends it when rel is NULL.

changed e_gadcon_util_client_menu_append to to take only the gadget menu
 and returns the new toplevel menu that should be shown by gcc
 depending on the setting this is a new menu with gadget menu as submenu
 or the gadet_menu with gadget menu items appended

updated e-modules-extra comes in a minute

SVN revision: 57826