PlayerThread: rename player_create() to StartPlayerThread()
decoder/dsf: fix indent
Report bitrate for DSF and DSDIFF DSD decoders
decoder/dsf: Allow up to DSD512. Enable DSD rates based on Fs=48kHz
input/ffmpeg: use "auto"
input/ffmpeg: refactor error code path
input/ffmpeg: update offset after seeking
{input,decoder}/ffmpeg: move ffmpeg_domain to lib/ffmpeg/Domain.cxx

Eliminate duplicate definition (in input plugin and decoder plugin).
input/ffmpeg: use av_strerror()

Generate more detailed error messages.
decoder/audiofile: check InputStream::KnownSize()

The plugin assumes that the size is known, but does not verify it at
runtime.
InputStream: use KnownSize() in assertion