- Added tomdoc inline documentation, indicating what is internal and public methods, properties, and options
- Changed some of the internal functionality
- Plugins can now also do `module.exports.extension = {method, type, ...}`, which is useful for existing modules that want to become chainy extensions, or similar situations where the top level export is not a chainy plugin method
- Plugins can now also do `module.exports.extensionOptions = {}`, which is useful when the top level export is a chainy plugin, but you also want to customise other options of it than just the `extensionType`
- Fixed mixin helper