The [Draft Oauth Token Exchange RFC](https://tools.ietf.org/html/draft-ietf-oauth-token-exchange-14) changed the `scope` attribute from `scp` to `scope`. This release supports both `scope` and `scp`, though support for `scp` will be removed in a future release.
Other changes (also part of 1.1 release):
- Use a shorter `kid` when creating a private / public key pair.
- Add support for elliptical curve signed keys.