Fix for pulling in right shoes-package bits

Formerly was including from Furoshiki, but now the pieces we need are in `shoes-package`.

Does this look right @wasnotrice? Had it working locally, so figured I'd PR to your branch instead of trying to describe in comments and/or muddy up your PR with my commit without checking.

FWIW, with this I was able to package and run successfully (with my gems from source no less, which didn't seem to work for me before!) \o/