elm genlist: Fixed flipmode cache issue. Renamed nocache to nocache_once and adopted nocache forever concept.
elm genlist: Fixed flipmode cache issue. Renamed nocache to nocache_once and adopted nocache forever concept.

Signed-off-by: Daniel Juyung Seo <juyung.seo@samsung.com>

SVN revision: 68756

tasn/elementary,FlorentRevest/Elementary,FlorentRevest/Elementary,rvandegrift/elementary,rvandegrift/elementary,tasn/elementary,FlorentRevest/Elementary,tasn/elementary,tasn/elementary,tasn/elementary,FlorentRevest/Elementary,rvandegrift/elementary,rvandegrift/elementary