- Rename `strictish` to `strict_only` in `add_error` method.
- Return just `errors`, a Set, not `{ errors: errors }`, a Hash,
from `Auditor.audit`.
- Rename `strictish` to `strict_only` in `add_error` method.
- Return just `errors`, a Set, not `{ errors: errors }`, a Hash,
from `Auditor.audit`.