Wrap async_chat instead of inheriting?

[tdoylend]

Currently, Channel inherits from async_chat. This means it gets the really wonky async_chat.getattr method, which causes problems like this.

I propose that instead of inheriting, we make Channel (and also EndPoint, by extension) a wrapper around async_chat. That way, error messages can be more helpful and PodSixNet can move closer to PEP-8 by not having capitalized methods.

I'm willing to do this and submit a PR if @chr15m thinks this is a good idea.

[chr15m]

Excellent, sounds great, thanks @tdoylend! This could help the Python 3 port as well. Let me know when there is a PR to review.

[chr15m]

@tdoylend feel free to re-open this if you submit such a PR. Thanks!