Rsynth Versions Save

This release adds nothing over the previous release; it is only used to mark rsynth as deprecated.

The polyphony module is deprecated in favour of a dedicated crate. The purpose is to limit the scope of rsynth. The two crates are completely separate. I think this increases the modularity in the eco-system.

Speaking of modularity: the sample crate into many different crates under the umbrella of dasp. This allowed me to only pick what is needed for rsynth.

Other changes:

• Envelopes have been deprecated and will be removed in a future release. No alternative is provided since the code was premature.
• Re-export jack-specific data types.
• Give access to jack backend in callbacks.
• Implement Display and Error for HoundAudioError and for CombinedError in order to facilitate debugging and error handling.

The copyright notices in the Cargo.toml and the README.md were inconsistent. This has now been fixed, clarifying that rsynth is dual linced under MIT or 3 clause BSD. We plan to move to MIT/Apache v2 in a future release (same license as Rust itself).

This corresponds to version 0.1.0 as published on crates.io.