Start using attrs instead of namedtuple about architecture

[balloob]

One of the advantages of attrs over namedtuple is default values. Now I tend to convert a namedtuple to a class whenever I want to add default values to avoid this:

Message = namedtuple('Message', ['topic', 'payload', 'qos', 'retain'])
Message.__new__.__defaults__ = (0, False)

[pvizeli]

Looks amazing. I don't like namedtuple anyway :)

[balloob]

We're using attrs now!