Update pub to use new import syntax.

utils/pub/package.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // 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('package');
+library package;
 
-#import('io.dart');
-#import('pubspec.dart');
-#import('source.dart');
-#import('source_registry.dart');
-#import('version.dart');
+import 'io.dart';
+import 'pubspec.dart';
+import 'source.dart';
+import 'source_registry.dart';
+import 'version.dart';
 
 /**
  * A named, versioned, unit of code and resource reuse.
  */
 class Package {
   /**
    * Loads the package whose root directory is [packageDir]. [name] is the
    * expected name of that package (e.g. the name given in the dependency), or
    * null if the package being loaded is the entrypoint package.
    */
@@ skipping 191 matching lines @@
 
 class PubspecNameMismatchException implements Exception {
   final String expectedName;
   final String actualName;
 
   PubspecNameMismatchException(this.expectedName, this.actualName);
 
   String toString() => 'The name you specified for your dependency, '
     '"$expectedName", doesn\'t match the name "$actualName" in its pubspec.';
 }