elm_focus: implement elm_object_focus_next_item_set / get
you can use this now to let the focus move to the widget container of
the passed item.
I know this patch contains a whitespace change, but i have to get out
this whitespace each & every time i am editing the file - which is
annoying. So remove it once, which makes further work easier.
Reviewed-by: YeongJong Lee <email@example.com>
Differential Revision: https://phab.enlightenment.org/D7408