integration with ircdef

[lrstanley]

Once I've solidified how I want https://github.com/lrstanley/ircdef to look, may want to look at moving to it for girc. Would definitely be a big change.

[lrstanley]

An additional usecase which may make this less of a breaking change, is type aliases. It's only recommended that they're used for migrations/backwards-compatible style changes, but still perfect for this usecase.