version 2.2.0

• support conversion into/from arbitrary types
• add ""_toml literal
• add find_or
• fix toml::format for table not to make top-level table inline
• fix format of duplicate sign in timezone
• fix add missing const specifier to a overload of get
• fix overload resolution and type deduction of get_or
• consider invalid utf-8 sequences as a syntax error
• remove deprecated to_toml
• mark get_or(table, key, fallback) deprecated because find_or is more clear
  • get_or(value, fallback) is not deprecated