this adds a lock for when walking all the objects to generate render
commands for an async render. this allows even the object tree walk
plus update area caluclation to be moved off into async if every oject
that can change canvas state actually does so correctly. this change
adds all those lock block calls to synchronise with an async object
tree walk.
Before this change eo_add() used to create an object with 1 ref, and if
the object had a parent, a second ref.
Now, eo_add() always returns an object with 1 ref, and eo_add_ref()
preserves the old behaviour (for bindings).
eo_unref now un-parents if refcount is 0, and eo_del() is an alias for
eo_unref (will change to be a way to ensure an object is dead and goes
to zombie-land even if still refed).
Enable 3D features using --enable-evas-3d=yes when configuring.
APIs are exposed through Evas_3D.h.
Currently, evas-3d is being supported only on gl_x11 engine.
Conflicts:
src/lib/evas/Evas_Eo.h