fix(cookies): Make sure Cookies is injectable.

Also clean-up a few warnings and remove an unnecessary workaround
in the todo example.

Closes #856

Author: kasperl

example/web/todo.dart

@@ -72,9 +72,6 @@ class TodoController {
     serverController.init(this);
   }
 
-  // workaround for https://github.com/angular/angular.dart/issues/37
-  dynamic operator [](String key) => key == 'newItem' ? newItem : null;
-
   void add() {
     if (newItem.isEmpty) return;
 

lib/core_dom/cookies.dart

@@ -96,6 +96,7 @@ class BrowserCookies {
 /**
  *   Cookies service
  */
+@NgInjectableService()
 class Cookies {
   BrowserCookies _browserCookies;
   Cookies(this._browserCookies);

test/io/test_files/templates/main.dart

@@ -1,6 +1,6 @@
 library test_files.main;
 
-import 'package:angular/core/module_internal.dart';
+import 'package:angular/core/annotation.dart';
 import 'package:angular/tools/template_cache_annotation.dart';
 
 part 'partial.dart';