Support for DSF and DSD

[bigpilot]

Would it be possible to support the .dsf file format for DSD playback?

Some DACs like the ES9018 support DSD playback using PDM over I2S.

[pschatzmann]

I added a DSFDecoder.

For using the ES9018, there is a configuration option to output the bitstream instead the decoded pcm data. The DSFFormat can be accessed via a callback

[bigpilot]

Awesome! I'm gonna try it out as soon as I can.

If it works I'll start ripping all my SACDs to .dsf format.