Update to Python 3.7

[anaselmi]

Dataclasses can be used for a lot of components.

[toptea]

Just to let you know, there's a backport for Python 3.6.

pip install dataclasses

[anaselmi]

I did see that, but I'm planning on updating to Python 3.7 anyways because it doesn't clash with any of my code, and I'd rather not have to import dataclasses only to delete said imports in a few days. Also, I'm probably not going to work on components before Python 3.7 is out anyways.

[anaselmi]

Python 3.7 has been released