Add Codable support

[fl034]

Hey there,
would be great to be able to use native way of decoding as an alternative data mapping.
Other libraries like CSV.swift and CodableCSV already do this, but they lack of stream based data import.

[Jeehut]

@fl034 Thank you for requesting this feature. I think it makes sense and should also not be too hard to do. I'm not sure when I will have time to add the feature though, may take several months. If you would find the time to write it and post a PR, that would be awesome! :)

[fl034]

I'm trying out a few Swift CSV libraries for my current project. If this one is the one I will use eventually, I might find the time to implement it and make a PR. :)
I will keep you posted in this issue, if I start working on it, so that we won't end up doing the work twice :D.