fix(warnings): remove unused_code warnings from newest nightlies

Author: seanmonstar

src/header/internals/item.rs

@@ -3,8 +3,6 @@ use std::any::TypeId;
 use std::fmt;
 use std::str::from_utf8;
 
-use typeable::Typeable;
-
 use super::cell::{OptCell, PtrMapCell};
 use header::{Header, HeaderFormat};
 

src/server/response.rs

@@ -414,7 +414,6 @@ mod tests {
 
     #[test]
     fn test_no_content() {
-        use std::io::Write;
         use status::StatusCode;
         let mut headers = Headers::new();
         let mut stream = MockStream::new();