Replacing internal NameTuple instances with @dataclass usage

[nackjicholson]

No description provided.

[nackjicholson]

@xlevus You're the only person I know of that has depended on very very internal things to this library. This shouldn't affect you but I put it in a PR just so you'd be able to easily see the change in case it does break something for you.

[nackjicholson]

@xlevus Nevermind, this isn't merging. I forgot dataclasses were a py37 feature and this library still supports py36 for now.

[yanniskatsaros]

If you’d like to continue support for Python 3.6 and still use dataclasses, it can just be added as a pip installable dependency to those users. Here is the back port in case you’d be interested in doing so:

https://pypi.org/project/dataclasses/

[nackjicholson]

@yanniskatsaros Thanks, I have used that package before. I'm being a bit stubborn not wanting to add it as an install dependency only for 3.6. But I may end up doing that.