v1.1.1

Specified error for invalid file paths!
Returns an additional property, expiresIn, so we can all be lazy about converting dates!
Now including 4 whole unit tests!
Convenience CLI for development!

v1.0.2

Added the generation script, some comments, and updated the README a few times. That's about it!

(The two patch-version increments are from making small comment/README updates, and not knowing how else to get those to show on NPM.)