New range request module

This introduce a new 'range' module
to support encoding, decoding and validation of HTTP range requests.

src/headers/constants.rs

@@ -128,6 +128,9 @@ pub const PROXY_AUTHENTICATE: HeaderName = HeaderName::from_lowercase_str("proxy
 ///  The `Proxy-Authorization` Header
 pub const PROXY_AUTHORIZATION: HeaderName = HeaderName::from_lowercase_str("proxy-authorization");
 
+/// The `Range` Header
+pub const RANGE: HeaderName = HeaderName::from_lowercase_str("range");
+
 ///  The `Referer` Header
 pub const REFERER: HeaderName = HeaderName::from_lowercase_str("referer");
 

src/headers/mod.rs

@@ -9,6 +9,7 @@ mod into_iter;
 mod iter;
 mod iter_mut;
 mod names;
+pub mod range;
 mod to_header_values;
 mod values;