dvdplayer: simplify calculation of playing pts for audio
dvdplayer: sync large audio errors without playing with the clock
ffmpeg: bump to 2.5.2
ffmpeg: explicitly disable sdl
Merge pull request #6044 from FernetMenta/audio

dvdplayer: make audioplayer sync to dvdclock without changing it
Merge pull request #6062 from FernetMenta/ffmpeg

ffmpeg: bump to 2.5.2