Added AccessControl* family of headers.

Fixes #169

src/header/common/access_control/request_method.rs

@@ -0,0 +1,26 @@
+use std::fmt::{mod};
+
+use header;
+use header::shared;
+use method::Method;
+
+#[deriving(Clone)]
+struct AccessControlRequestMethod(pub Method);
+
+impl header::Header for AccessControlRequestMethod {
+    #[inline]
+    fn header_name(_: Option<AccessControlRequestMethod>) -> &'static str {
+        "Access-Control-Request-Method"
+    }
+
+    fn parse_header(raw: &[Vec<u8>]) -> Option<AccessControlRequestMethod> {
+        shared::from_one_raw_str(raw).map(AccessControlRequestMethod)
+    }
+}
+
+impl header::HeaderFormat for AccessControlRequestMethod {
+    fn fmt_header(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let AccessControlRequestMethod(ref method) = *self;
+        method.fmt(f)
+    }
+}