Add a getter for the HTTP referer

src/libfast/request.h

@@ -105,6 +105,13 @@ struct request_t {
 	 */
 	void (*redirect)(request_t *this, char *fmt, ...);
 
+	/**
+	 * Get the HTTP referer.
+	 *
+	 * @return			HTTP referer
+	 */
+	char* (*get_referer)(request_t *this);
+
 	/**
 	 * Redirect the client to the referer.
 	 */