feat(hyper): switch to std::io, std::net, and std::path.

All instances of `old_io` and `old_path` were switched to use the new
shiny `std::io`, `std::net`, and `std::path` modules. This means that
`Request` and `Response` implement `Read` and `Write` now.

Because of the changes to `TcpListener`, this also takes the opportunity
to correct the method usage of `Server`. As with other
languages/frameworks, the server is first created with a handler, and
then a host/port is passed to a `listen` method. This reverses what
`Server` used to do.

Closes #347

BREAKING CHANGE: Check the docs. Everything was touched.

src/header/common/host.rs

@@ -1,5 +1,4 @@
 use header::{Header, HeaderFormat};
-use Port;
 use std::fmt;
 use header::parsing::from_one_raw_str;
 
@@ -15,7 +14,7 @@ pub struct Host {
     /// The hostname, such a example.domain.
     pub hostname: String,
     /// An optional port number.
-    pub port: Option<Port>
+    pub port: Option<u16>
 }
 
 impl Header for Host {