TOML library for C++

Features

* Supports the latest TOML release (v1.0.0), plus optional support
  for some unreleased TOML features
* Supports serializing to JSON
* Proper UTF-8 handling (incl. BOM)
* C++17 (plus some C++20 features where available, e.g. experimental
  support for char8_t strings)
* Header-only (optional!)
* Doesn't require RTTI
* Works with or without exceptions