[x265] psycho-visual feature tuning, feature freeze

[Steve Borho]

Hello,

I've pushed some (what I hope to be) final tunings of the two new
psycho-visual optimization features. The features are still disabled by
default, but the recommended values are now 1.0 for both.

http://x265.readthedocs.org/en/stable/cli.html#psycho-visual-options

Please try them out.

The stable branch has been merged with default in preparation of a 1.3
tag, which should happen early this week.

-- 
Steve Borho