This is quite a large release relative to the previous point releases! As
with all 0.1 releases, this release should be fully compatible with the 0.1.3
release. If any incompatibilities are discovered please file an issue!

The largest changes in 0.1.4 are the addition of a `Sink` trait coupled with a
reorganization of this crate. Note that all old locations for types/traits
still exist, they're just deprecated and tagged with `#[doc(hidden)]`.

The new `Sink` trait is used to represent types which can periodically over
time accept items, but may take some time to fully process the item before
another can be accepted. Essentially, a sink is the opposite of a stream. This
trait will then be used in the tokio-core crate to implement simple framing by
modeling I/O streams as both a stream and a sink of frames.

The organization of this crate is to now have three primary submodules,
`future`, `stream`, and `sink`. The traits as well as all combinator types are
defined in these submodules. The traits and types like `Async` and `Poll` are
then reexported at the top of the crate for convenient usage. It should be a
relatively rare occasion that the modules themselves are reached into.

Finally, the 0.1.4 release comes with a new module, `sync`, in the futures
crate.  This is intended to be the home of a suite of futures-aware
synchronization primitives. Currently this is inhabited with a `oneshot` module
(the old `oneshot` function), a `mpsc` module for a new multi-producer
single-consumer channel, and a `BiLock` type which represents sharing ownership
of one value between two consumers. This module may expand over time with more
types like a mutex, rwlock, spsc channel, etc.

Notable deprecations in the 0.1.4 release that will be deleted in an eventual
0.2 release:

* The `TaskRc` type is now deprecated in favor of `BiLock` or otherwise `Arc`
  sharing.
* All future combinators should be accessed through the `future` module, not
  the top-level of the crate.
* The `Oneshot` and `Complete` types are now replaced with the `sync::oneshot`
  module.
* Some old names like `collect` are deprecated in favor of more appropriately
  named versions like `join_all`
* The `finished` constructor is now `ok`.
* The `failed` constructor is now `err`.
* The `done` constructor is now `result`.

As always, please report bugs to https://github.com/alexcrichton/futures-rs and
we always love feedback! If you've got situations we don't cover, combinators
you'd like to see, or slow code, please let us know!

Full changelog:

* Improve scalability of `buffer_unordered` combinator
* Fix a memory ordering bug in oneshot
* Add a new trait, `Sink`
* Reorganize the crate into three primary modules
* Add a new `sync` module for synchronization primitives
* Add a `BiLock` sync primitive for two-way sharing
* Deprecate `TaskRc`
* Rename `collect` to `join_all`
* Use a small vec in `Events` for improved clone performance
* Add `Stream::select` for selecting items from two streams like `merge` but
  requiring the same types.
* Add `stream::unfold` constructor
* Add a `sync::mpsc` module with a futures-aware multi-producer single-consumer
  queue. Both bounded (with backpressure) and unbounded (no backpressure)
  variants are provided.
* Renamed `failed`, `finished`, and `done` combinators to `err`, `ok`, and
  `result`.
* Add `Stream::forward` to send all items to a sink, like `Sink::send_all`
* Add `Stream::split` for streams which are both sinks and streams to have
  separate ownership of the stream/sink halves
* Improve `join_all` with concurrency