refactor(headers): changed from rwlock to mucell underneath
feat(headers): add Expires header
feat(headers): add LastModified header
feat(headers): add CacheControl header
Merge pull request #167 from hyperium/rustup

rust upgrade
Add more functions for client to work with cookies. Fixes #155.
Merge pull request #166 from s-panferov/feature/client-cookies

Add more functions for client to work with cookies.
Merge pull request #161 from hyperium/mucell

refactor(headers): changed from rwlock to mucell underneath
Merge pull request #165 from hyperium/expires

Adds CacheControl, Expires, and LastModified headers
Removed now-deprecated Equiv implementation
Merge pull request #176 from kyledewey/remove_equiv

Removed now-deprecated Equiv implementation
refactor(net): NetworkConnecter no longer is for static usage

Instead, you can use an instance of a NetworkConnector with
`Request::with_connector`. This allows overloading of the NetworkStream
constructors, so that it is easy to modify how an `HttpStream` is
created, while still relying on the rest of the stream implementation.

BREAKING CHANGE
Merge pull request #168 from hyperium/ssl-verify

r=reem
rustup
Merge pull request #181 from hyperium/rustup

rustup
feat(client): add a new Client struct with super powers

- Includes ergonomic traits like IntoUrl and IntoBody, allowing easy
usage.
- Client can have a RedirectPolicy.
- Client can have a SslVerifier.

Updated benchmarks for client. (Disabled rust-http client bench since it
hangs.)