v0.2.1

• Fixed bugs with decoder options only_ascii_source and
  only_ascii_unquoted.
• Prevent explicit typing of none, true, and false.
• Tag keyword indent no longer affects text after an escaped newline.
• Fixed bug that prevented inline collections from being tagged if not at line
  start.
• RootNode and DictlikeNode now have _state attribute.
• Improved grammar.