Only use async/await coroutine style in asyncio framework

[touilleMan]

No description provided.

[coveralls]

Coverage decreased (-9.7%) to 86.636% when pulling cba51a6 on move-asyncio-to-await-syntax-only into db9b4b7 on master.

[lafrech]

Thanks for tackling this.

Looks like you're using asynchronous comprehensions, introduced in Python 3.6:
https://docs.python.org/3/whatsnew/3.6.html#pep-530-asynchronous-comprehensions

[lafrech]

I fixed the 3.5 compatibility issue. Tests pass.

I can't really provide an educated review as I'm async illiterate. I'll trust you on this one and merge as is.

[touilleMan]

@lafrech hooop I didn't notice your fix !

I though we were also dropping Python 3.5 so I pushed --force and destroyed your fix ! (I should have used --force-with-lease...)

Can you re-push this branch with your fix please ?

[lafrech]

Ah ah. No pb. Done.

It takes a little more to run tests on 3.7. We need to tell Travis to use Xenial. I'll do that if you want when this is merged. #180.

Edit: see PR #181 for 3.7 support.