Begin WebSocket support for Broadcast and Player control

modules/Guzzle/Http/Message/Header/HeaderFactoryInterface.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace Guzzle\Http\Message\Header;
+
+/**
+ * Interface for creating headers
+ */
+interface HeaderFactoryInterface
+{
+    /**
+     * Create a header from a header name and a single value
+     *
+     * @param string $header Name of the header to create
+     * @param string $value  Value to set on the header
+     *
+     * @return HeaderInterface
+     */
+    public function createHeader($header, $value = null);
+}