Merge pull request #164 from donmccurdy/feat-ipv6-host-header

Include brackets for IPv6 host header.

lib/XMLHttpRequest.js

@@ -111,7 +111,7 @@ exports.XMLHttpRequest = function() {
   this.responseXML = "";
   this.status = null;
   this.statusText = null;
-  
+
   // Whether cross-site Access-Control requests should be made using
   // credentials such as cookies or authorization headers
   this.withCredentials = false;
@@ -343,6 +343,10 @@ exports.XMLHttpRequest = function() {
 
     // Set the Host header or the server may reject the request
     headers.Host = host;
+    // IPv6 addresses must be escaped with brackets
+    if (url.host[0] === "[") {
+      headers.Host = "[" + headers.Host + "]";
+    }
     if (!((ssl && port === 443) || port === 80)) {
       headers.Host += ":" + url.port;
     }