Rename to tokio-core, add in futures-io

Renames the futures-mio crate to tokio-core, pulls in the futures-io crate under
an `io` module, and gets everything compiling.

src/io/mod.rs

@@ -0,0 +1,47 @@
+//! I/O conveniences when working with primitives in `tokio-core`
+//!
+//! Contains various combinators to work with I/O objects and type definitions
+//! as well.
+
+use std::io;
+
+use futures::BoxFuture;
+use futures::stream::BoxStream;
+
+/// A convenience typedef around a `Future` whose error component is `io::Error`
+pub type IoFuture<T> = BoxFuture<T, io::Error>;
+
+/// A convenience typedef around a `Stream` whose error component is `io::Error`
+pub type IoStream<T> = BoxStream<T, io::Error>;
+
+/// A convenience macro for working with `io::Result<T>` from the `Read` and
+/// `Write` traits.
+///
+/// This macro takes `io::Result<T>` as input, and returns `T` as the output. If
+/// the input type is of the `Err` variant, then `Poll::NotReady` is returned if
+/// it indicates `WouldBlock` or otherwise `Err` is returned.
+#[macro_export]
+macro_rules! try_nb {
+    ($e:expr) => (match $e {
+        Ok(t) => t,
+        Err(ref e) if e.kind() == ::std::io::ErrorKind::WouldBlock => {
+            return ::futures::Poll::NotReady
+        }
+        Err(e) => return ::futures::Poll::Err(e.into()),
+    })
+}
+
+mod copy;
+mod flush;
+mod read_exact;
+mod read_to_end;
+mod task;
+mod window;
+mod write_all;
+pub use self::copy::{copy, Copy};
+pub use self::flush::{flush, Flush};
+pub use self::read_exact::{read_exact, ReadExact};
+pub use self::read_to_end::{read_to_end, ReadToEnd};
+pub use self::task::{TaskIo, TaskIoRead, TaskIoWrite};
+pub use self::window::Window;
+pub use self::write_all::{write_all, WriteAll};