RealVideo NEON optimization

[ibiris 16jan2012]: moving back to backlog, needs to be planned for a monthly milestone
[tom-gall 23jan2012]: discussed with mans, removing strong deblocking filter work item as the return is probably on the order of a 2% improvement.
[benjamin-gaignard]: lava test definition uploaded here:
http://git.linaro.org/gitweb?p=people/bgaignard/lava_realvideo_test.git;a=summary
[benjamin-gaignard]: lava test run example: https://validation.linaro.org/lava-server/scheduler/job/11619
[benjamin-gaignard]: lava test result example (measurement field):
http://validation.linaro.org/lava-server/dashboard/streams/anonymous/USERNAME/bundles/12420882c001b939aab46115cf740b33d6a6a3c4/3a303f30-5200-11e1-aed0-2e4034a96c0a/

Initial patch set exists, needs review and further optimisation.
http://thread.gmane.org/gmane.comp.video.libav.devel/11181

Meta:
Roadmap id: MMWG2011-SW-CODEC-OPTIMIZATION
Headline:
NEON optimisations to the Realvideo decoder enables software playback of video in this format on ARM-based devices.

Acceptance:
Substantial speedup of Realvideo decoding.

Work items:
Inverse transform: DONE
Chroma MC: DONE
Weighted MC: DONE
Qpel MC: DONE
Dequantisation: DONE
Weak deblocking filter: DONE
[benjamin-gaignard] Benchmarks for LAVA: DONE