This commit makes a few tweaks to the new `easy` module:
- Rename `Parse` to `Decode`, and `Serialize` to `Encode`.
- Don't use `Poll` for the `decode` method; we prefer to reserve
that type for actual aync events, and in particular for a `NotReady`
result to imply that some task scheduling has taken place. Instead,
use an internal `Option`.
This commit extracts the concrete implementation of `FrameIo` in tokio-proto to
tokio-core under the name `EasyFramed`. This extraction is accompanied with a
new `EasyBuf` buffer type to work with when parsing types.
The purpose of this movement is to provide a clear and easy entry point at the
`FramedIo` layer for those who need it. Eventually these buffer types will get
replaced or moved to the `bytes` crate, but in the interest of an 0.1 release
and remaining backwards compatible with the tokio-core 0.1 release this is
adding a separate module.
Aaron Turon