unbreak elm_menu_item api

unbreak elm_menu_item api

the following functions are now DEPRECATED and will be removed on 5 AUG 2011:
elm_menu_item_object_icon_get -> elm_menu_item_object_content_get
elm_menu_item_icon_get -> elm_menu_item_object_icon_name_get
elm_menu_item_icon_set -> elm_menu_item_object_icon_name_set

added the following NEW functions:
elm_menu_item_object_content_set
elm_menu_item_menu_get (this will probably be replaced by an eventual elm_object_item_owner_get() or whatever it gets named)

git-svn-id: https://svn.enlightenment.org/svn/e/trunk/elementary@61899 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33