feat(headers): adds re-parsing ability when getting typed headers

BREAKING CHANGE: added requirement that all HeaderFormat implementations
  must also be fmt::Debug. This likely as easy as slapping
  #[derive(Debug)] on to any custom headers.

src/lib.rs

@@ -130,7 +130,6 @@ extern crate "rustc-serialize" as serialize;
 extern crate time;
 extern crate url;
 extern crate openssl;
-extern crate "unsafe-any" as uany;
 extern crate cookie;
 extern crate unicase;