x265: new package

x265 is a H.265 / HEVC video encoder application library, designed to encode
video or images into an H.265 / HEVC encoded bitstream.

http://x265.org



[Peter: use positive logic for CLI option]
Signed-off-by: Thijs Vermeir <thijsvermeir@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>