Some names have not been changed, hopefully making a distinction
between legacy APIs and internal code (elm_layout_blah) and valid EO
usages.
This means many internal functions are still elm_layout_ as their
sole purpose is to support the legacy API.
Ref T5315
Previously events used to use class name as a prefix and ignored eo_prefix
when specified. This is no longer the case. Events follow eo_prefix by default
now. In order to get around this for classes where this is undesirable, a new
field event_prefix was added which takes priority over eo_prefix. If neither
is specified, class name is used like previously.
@feature