add evas_object_box.

add evas_object_box.

Box is a smart object to help with the common task of laying out lots
of objects. It's very flexibile and one can customize the layout
function on a per-object basis dynamically, just set a new layout
function (the most common are provided). By default layouts use size
hints from children to do their work, but one can also add new
properties, just subclass with evas_object_smart_smart_set() and then
define your own option_* callbacks.

This code was ported from Guarana (widgets/sequence_box.c) with
permission of ProFUSION embedded systems so it can be relicensed from
LGPL to Evas license.

Original author: Gustavo Lima Chaves <glima@profusion.mobi>
Port: Gustavo Sverzut Barbieri <barbieri@profusion.mobi>

git-svn-id: svn+ssh://svn.enlightenment.org/var/svn/e/trunk/evas@37188 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33