Expect turbulence as this package is extracted from dappsys.
Token implementation using frontend/controller/datastore contracts for upgradeability.
The factory installs "into" a DSBasicAuthority (see ds-auth).
If this is overkill for your dapp and overriding a single-contract implementation is sufficient, consider nexusdev/erc20.
https://steemit.com/ethereum/@nikolai/dapp-a-day-6-upgradeable-tokens