Add topl (Node.js/Browser) lib to list of decoders

I have added support for `toml-test` to my Node.js/Browser TOML decoder, [topl](https://github.com/redhotvengeance/topl). This PR adds it to your list.

As of right now, `topl` fully passes the `toml-test` test suite, though only the tweaked one submitted in #13 (with JS-specific fixes in it).