Upgrade eslint & commander (out of current ranges)

[Throne3d]

The only scary changelog here is commander, which has jumped from v2 to v4 without a v3 and without much in the way of migration information.

However, since we only use it in lib/cli.js, and npm start -- --help and npm start -- --config=config.json both work after this change, it sure looks like we're fine to update this.

eslint is behaving fine – doesn't look like any of it affects us.

[coveralls]

Coverage remained the same at 97.126% when pulling 1836f19 on Throne3d:upgrade/deps-2019-12-14 into 33d12d7 on reactiflux:master.