Migrate actix-net to std::future (#64)

* Migrate actix-codec, actix-rt, and actix-threadpool to std::future

* update to latest tokio alpha and futures-rs

* Migrate actix-service to std::future,

This is a squash of ~8 commits, since it included a lot of experimentation. To see the commits,
look into the semtexzv/std-future-service-tmp branch.

* update futures-rs and tokio

* Migrate actix-threadpool to std::future (#59)

* Migrate actix-threadpool to std::future

* Cosmetic refactor

- turn log::error! into log::warn! as it doesn't throw any error
- add Clone and Copy impls for Cancelled making it cheap to operate with
- apply rustfmt

* Bump up crate version to 0.2.0 and pre-fill its changelog

* Disable patching 'actix-threadpool' crate in global workspace as unnecessary

* Revert patching and fix 'actix-rt'

* Migrate actix-rt to std::future (#47)

* remove Pin from Service::poll_ready(); simplify combinators api; make code compile

* disable tests

* update travis config

* refactor naming

* drop IntoFuture trait

* Migrate actix-server to std::future (#50)

Still not finished, this is more WIP, this is an aggregation of several commits, which
can be found in semtexzv/std-future-server-tmp branch

* update actix-server

* rename Factor to ServiceFactory

* start server worker in start mehtod

* update actix-utils

* remove IntoTransform trait

* Migrate actix-server::ssl::nativetls to std futures (#61)

* Refactor 'nativetls' module

* Migrate 'actix-server-config' to std futures

- remove "uds" feature
- disable features by default

* Switch NativeTlsAcceptor to use 'tokio-tls' crate

* Bikeshed features names and remove unnecessary dependencies for 'actix-server-config' crate

* update openssl impl

* migrate actix-connect to std::future

* migrate actix-ioframe to std::future

* update version to alpha.1

* fix boxed service

* migrate server rustls support

* migratte openssl and rustls connecttors

* store the thread's handle with arbiter (#62)

* update ssl connect tests

* restore service tests

* update readme

actix-rt/src/system.rs

@@ -2,9 +2,9 @@ use std::cell::RefCell;
 use std::io;
 use std::sync::atomic::{AtomicUsize, Ordering};
 
-use futures::sync::mpsc::UnboundedSender;
+use futures::channel::mpsc::UnboundedSender;
 use futures::Future;
-use tokio_current_thread::Handle;
+use tokio::runtime::current_thread::Handle;
 
 use crate::arbiter::{Arbiter, SystemCommand};
 use crate::builder::{Builder, SystemRunner};
@@ -64,7 +64,7 @@ impl System {
     pub fn run_in_executor<T: Into<String>>(
         name: T,
         executor: Handle,
-    ) -> impl Future<Item = (), Error = io::Error> + Send {
+    ) -> impl Future<Output = Result<(), io::Error>> + Send {
         Self::builder()
             .name(name)
             .build_async(executor)