Update utils to new library syntax.

utils/css/tool.dart

Index: utils/css/tool.dart
===================================================================
--- utils/css/tool.dart	(revision 14646)
+++ utils/css/tool.dart	(working copy)
@@ -2,12 +2,12 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-#library('csstool');
+library csstool;
 
-#import('dart:io');
-#import('css.dart');
-#import('../lib/file_system.dart');
-#import('../lib/file_system_vm.dart');
+import 'dart:io';
+import 'css.dart';
+import '../lib/file_system.dart';
+import '../lib/file_system_vm.dart';
 
 
 FileSystem files;