this currently has no counterpart in interface widgets but would be
useful there. removing the use of an elm_scroller type makes it independent
of legacy widgets, and it's still a beta api so at least future development
can be resumed at some point without much issue
Reviewed-by: Cedric BAIL <cedric.bail@free.fr>
Differential Revision: https://phab.enlightenment.org/D8158
Mike Blumenkrantz