add header comments

lib/router.dart

@@ -1,3 +1,10 @@
+/*
+ * router
+ * A Posse Production
+ * http://goposse.com
+ * Copyright (c) 2017 Posse Productions LLC. All rights reserved.
+ * See LICENSE for distribution and usage details.
+ */
 library router;
 
 import 'package:flutter/foundation.dart';

lib/src/common.dart

@@ -1,3 +1,10 @@
+/*
+ * router
+ * A Posse Production
+ * http://goposse.com
+ * Copyright (c) 2017 Posse Productions LLC. All rights reserved.
+ * See LICENSE for distribution and usage details.
+ */
 part of router;
 
 ///

lib/src/router.dart

@@ -1,3 +1,10 @@
+/*
+ * router
+ * A Posse Production
+ * http://goposse.com
+ * Copyright (c) 2017 Posse Productions LLC. All rights reserved.
+ * See LICENSE for distribution and usage details.
+ */
 part of router;
 
 enum TransitionType {

lib/src/tree.dart

@@ -1,3 +1,10 @@
+/*
+ * router
+ * A Posse Production
+ * http://goposse.com
+ * Copyright (c) 2017 Posse Productions LLC. All rights reserved.
+ * See LICENSE for distribution and usage details.
+ */
 part of router;
 
 enum RouteTreeNodeType {