Add MIR-1K

[carlthome]

https://sites.google.com/site/unvoicedsoundseparation/mir-1k

I could do this.

[justinsalamon]

Which annotations did you have in mind? We're in the process of refactoring the pitch namespaces, if you were thinking of migrating the f0 annotations you might want to wait until that's in place.

[carlthome]

Cool. I'll wait a bit then. 😄