ffmpeg 3.3 - gpac 7.0 - x264/x265 need update

Hi, I know Leigh is already working on ffmpeg 3.3, but others libraries also needs update. It would be fine to have them updated all along, in f27 and then maybe f26. There is no SONAME bump with this ffmpeg compared to 3.3,but this doesn't mean there is no need for a rebuild because they are still some data structure changes. At least it would be more safe if a rebuild can be made. Thx -- - Nicolas (kwizart)