efl: roll in first use of Eina_Cow for Evas_Object.proxy.
Expedite biggest test memory win 100KB, average 10KB. No slow down in proxy test (+/-3%). Speed up in most other case (average speed up is +5%), likely due to much more cache hit.
Elementary test show a win between 100KB to 600KB depending on the test you are considering.
Now, you can see how I intend to use Eina_Cow and the expected win we can have from it. I don't intend to do more for the rest of the week so you have time to comment.