evas: improvement of Eina Rectangle Pool and integration with Evas GL backend.

evas: improvement of Eina Rectangle Pool and integration with Evas GL backend.

Summary:
This patch introduce various new logic for packing/unpacking of Eina Rectangle in a pool.
It is then used by Evas GL backend texture allocation to improve how efficiently we pack
image in texture atlas. This lead to improved memory usage and reduced power consumption
with usually a more stable higher FPS (as it use less texture to do the same task, their
is less texture switch, so saving memory and speed at the same time).

This patch was developped on Cedric's suggestions to optimize the packing logic using Skyline
algorithm. This patch is based on master and is a new submission for earlier phab link
https://phab.enlightenment.org/D774.

Signed-off-by: Sanjay Nirankari <sanjay.n1@samsung.com>
Signed-off-by: Rajeev Ranjan <rajeev.r@samsung.com>
Signed-off-by: Sreedeep Moulik <sreedeep.m@samsung.com>
Reviewers: cedric, raster

CC: wonsik, jpeg, sreedeep.m, sanjay, govi
Differential Revision: https://phab.enlightenment.org/D1063

Signed-off-by: Cedric BAIL <c.bail@partner.samsung.com>