oggparsevorbis: support official chapter extension

Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
oggparsevorbis: check allocations

Signed-off-by: Anton Khirnov <anton@khirnov.net>
oggdec: add support for Opus in Ogg demuxing
flac: move picture parsing code in a separate file

Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
oggvorbisdec: add support for embedded cover art

Signed-off-by: James Almer <jamrial@gmail.com>
oggparsevorbis: fail on memory allocation error