This shows how to implement a layout function, with the
required Eo class boilerplate (note: could probably be
simpler with the appropriate macros, or a better solution
to create classes on the fly in C).
The layout function itself is awful, but shows that "it works".
This reuses the Evas.Box code, since we are still using the
box internally. The flow layout function is far from perfect
(it works well only with items of same height).
This shows how to use specific layouts provided by EFL.
Jean-Philippe Andre