Full Changelog: v3.0.0...v3.1.0
- Fix #12 by @astares - Remove deprecated XMLDoctypeDeclarationWriter>>#withInternalSubset:
- Fix #13 by @astares - Cleanup: use #isNotNil instead of #notNil
- Fix #14 by @astares - Cleanup: deprecate #notEmpty and use #isNotEmpty
- Fix #15 by @astares - Cleanup: XMLWriterFormatter should be abstract
