Integrate the 'http' crate

[bradleybeddoes]

This was recently announced at https://users.rust-lang.org/t/announcing-the-http-crate/12123.

We'll need support in Hyper before we can migrate to this but once that has occurred we should be able to get there quite quickly given the way we've already made use of similar types from Hyper directly instead of reinventing this particular wheel.

https://github.com/carllerche/http
https://carllerche.github.io/http/http/index.html

[n-pochet]

Hi,
I looked a little bit about that yesterday and it seems that Hyper is providing compatibility with the http crate by using the compat feature in Hyper.
What is still unclear for me is the amount of rework that such change would imply.
How far would we like to go with the integration?

[bradleybeddoes]

I'm actually a little ways down the rabbit hole on this one, there is a reasonable amount of change going on, more than I anticipated but not unachievable.

I am considering holding that effort until Hyper 0.12 comes along which remove the compat feature flag and integrate with the http crate directly (or so I understood it to be anyways from a brief reddit discussion I had with @seanmonstar).

Either way this won't ship with Gotham 0.2, which is firming up for late February now.

[whitfin]

@nyarly would you say we can close this given the Hyper 0.12 migration?