Added
- Implement `resin.models.device.getManifestByApplication()`.
- Implement `resin.models.device.register()`.
- Check that device/application exists before attempting to remove.
Changed
- Fix environment variables documentation.
- Fix `resin.models.key.get()` `undefined` issue.
- Fix `resin.models.key.create()` bug that caused no key to be created.
- Fix `resin.models.application.create()` example issue with device slugs.
- Upgrade `resin-errors` to v2.0.0.
- Upgrade `resin-request` to v2.2.3.
- Upgrade `resin-token` to v2.4.1.