Roll Observatory packages and add a roll script

packages/initialize/lib/build/initializer_plugin.dart

 // Copyright (c) 2015, 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 initialize.build.initializer_plugin;
 
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:barback/barback.dart';
 import 'package:code_transformers/resolver.dart';
 import 'package:initialize/transformer.dart';
@@ skipping 274 matching lines @@
     return value;
   }
 
   // Returns an expression for a string value. Wraps it in single quotes and
   // escapes existing single quotes and escapes.
   _stringValue(String value) {
     value = value.replaceAll(r'\', r'\\').replaceAll(r"'", r"\'");
     return "'$value'";
   }
 }