add metatune param

[ahihi]

adds support for the metatune functionality recently merged into SuperDirt.

to summarize:

• WAV files can contain pitch metadata in a smpl chunk, commonly used by samplers for automatic pitch mapping
• SuperDirt now reads and stores this metadata for each loaded sample
• when the dirt_sample synth is passed metatune = 1, it tunes sample playback relative to the sample's pitch metadata

so given e.g. an instrument sample foo:2 recorded at F#4 and tagged as such in its metadata, it is now possible to do d1 $ note "c3" # s "foo:2" # metatune 1 and it will actually play at C3!

metatune defaults to 0, in which case C4 is used as the reference pitch, just like before. C4 is also the fallback when metatune = 1 but the specified sample lacks pitch metadata.

[yaxu]

Thanks! I'm in the process of moving things around on the cycseq branch. I'll leave this PR open for now, and merge after #1031.

[matthewkaney]

@ahihi Thanks! Would you mind submitting a PR with this change against the 1.9-dev branch? We're using the main branch for developing Tidal 2.0, but if you submit a patch on that branch it can get published sooner!

[ahihi]

sure thing! closing this one.