ULV 2.0 file specification

[severikasurinen]

The ULV 1.0 file specification lacks in future-proofing, and should be replaced by a new (incompatible) file specification (2.0) with some extra bytes before sample data for possible configuration data, such as audio/mechanical sample rate or bit depth information, also enabling PWM and other functionality to be added later on. This could be implemented by e.g. reserving the first cluster for configuration data and starting the song read from the first byte of the second data cluster.