feat(headers): Add From header field

src/header/common/from.rs

@@ -0,0 +1,18 @@
+header! {
+    #[doc="`From` header, defined in [RFC7231](http://tools.ietf.org/html/rfc7231#section-5.5.1)"]
+    #[doc=""]
+    #[doc="The `From` header field contains an Internet email address for a"]
+    #[doc="human user who controls the requesting user agent.  The address ought"]
+    #[doc="to be machine-usable."]
+    #[doc="# ABNF"]
+    #[doc="```plain"]
+    #[doc="From    = mailbox"]
+    #[doc="mailbox = <mailbox, see [RFC5322], Section 3.4>"]
+    #[doc="```"]
+    // FIXME: Maybe use mailbox?
+    (From, "From") => [String]
+
+    test_from {
+        test_header!(test1, vec![b"[email protected]"]);
+    }
+}

src/header/common/mod.rs

@@ -29,6 +29,7 @@ pub use self::date::Date;
 pub use self::etag::ETag;
 pub use self::expect::Expect;
 pub use self::expires::Expires;
+pub use self::from::From;
 pub use self::host::Host;
 pub use self::if_match::IfMatch;
 pub use self::if_modified_since::IfModifiedSince;
@@ -315,6 +316,7 @@ mod date;
 mod etag;
 mod expect;
 mod expires;
+mod from;
 mod host;
 mod if_match;
 mod if_modified_since;