separate out response

src/agent.rs

@@ -1,12 +1,12 @@
 use cookie::{Cookie, CookieJar};
-use std::str::FromStr;
+use error::Error;
+use response::{self, Response};
 use std::sync::Mutex;
 
-use header::{add_header, get_header, get_all_headers, has_header, Header};
+use header::{add_header, get_all_headers, get_header, has_header, Header};
 
 // to get to share private fields
 include!("request.rs");
-include!("response.rs");
 include!("conn.rs");
 include!("stream.rs");
 include!("unit.rs");