- key switches (details: sw_down, sw_up)
- envelope minimum times (prevent clicks)
- C++ style block comments
- implement better interpolation (windowed sinc, bandlimited interpolation)
- possibly contstrain parameters (however, sforzando doesn't always constrain either)

maybe:
- aria xml index
- maintain active voice list
- implement sustain loop

------------ NEW RELEASE ------------

- make distcheck
- update NEWS
- update opcode list
- make rebuild-api-docs
- update README.md
- upload static build
- upload tarball
- git tag

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