add support for dumping to specific file

[RiedleroD]

having -w is already nice on its own, but it's a bit tedious to handle e.g. in scripts when I need to make sure several threads don't interfere. Currently I copy the vgm file to /tmp/ so I can make sure vgmplay doesn't overwrite an existing file, but this is not optimal.

[ValleyBell]

How would we handle playlists / multiple files there?

[RiedleroD]

…good question. You could limit this feature to only working for single files I guess?

Other options:

• making the user supply a output file path for each input file / track in playlist
• supporting format strings, similar to how ffmpeg does it (%02d and such)