This touches Edje and also Elementary where part names are used.
This commit blew up in size since now all content part APIs
(get, set, unset) require to use Efl.Part instead.
This is a big refactoring commit, but no logic should
have been changed. Fingers crossed.
This removes Efl.Pack_Named which had a terrible name,
removes Elm.Container which should have been renamed
Efl.Ui.Container anyway, and introduces an interface
Efl.Container instead.
The hierarchy tree is now changed as objects don't inherit
from Efl.Container (it's an interface, not a regular class)
but only implement it. Obviously it is very easy to
reintroduce an Efl.Ui.Container parent class if we need it,
but I guess it should have some actual logic. It's basically
part of what Elm.Widget already does.
Some function names have been modified to look better in C
with the efl_content prefix.
@feature
Jean-Philippe Andre
Tom Hacohen
Stefan Schmidt
Cedric BAIL