[Fix] Possible NULL pointer dereference in DVDFactoryDemuxer.
[ffmpeg] updated and reformated ffmpeg/patches/README-patches
Merge pull request #2635 from FlyingRat/ffmpeg-readme-patches

[ffmpeg] updated and reformated ffmpeg/patches/README-patches
[dvdread] - don't check the return value of chdir in xbmc - this function is not wrapped and might fail (and so will the whole dvd open in that case). This is non fatal for our vfs!
Merge pull request #2632 from ace20022/fix_null_pointer

[Fix] Possible NULL pointer dereference in DVDFactoryDemuxer.