Netlint

- Fix ACL definition syntax for standard ACLs
- Re-introduce `-p/--plain` in addition to `-q/--quiet`

- Remove `--nos` in favor of automatic NOS syntax detection
- Add new checks (see [here](https://netlint.readthedocs.io/en/latest/nos/index.html)) for exact information on currently supported checks)
- Implement `--config` to allow for configuration files
- Add documentation on how to integrate `netlint` with [Oxidized](https://github.com/ytti/oxidized)

Initial release