Add interpolate() to Music VAE (#1301)
Add interpolate() to Music VAE (#1301)

* add an interpolate method to music_vae

* prettify the names in midi_io

* more, and use the new names in some places

* review comments

* better comment

* review comments

* fix lint errors

* review comments

magenta/magenta,jesseengel/magenta,adarob/magenta,magenta/magenta,jesseengel/magenta,adarob/magenta