Draft for review. This specification isn't authoritative until the Clone Hero and YARG developers have approved it, and scan-chart 9.0.0 isn't released yet.
Parses a song folder into a document. Only the chart and .ini files are read; other files, such as audio, video
and album art, can be byte sources, and are read only when something needs them. Never rejects: a malformed chart
or song.ini is reported when it’s read.