Roll Observatory packages and add a roll script

packages/dart_style/lib/src/dart_formatter.dart

 // Copyright (c) 2014, 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 dart_style.src.dart_formatter;
 
 import 'dart:math' as math;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/src/generated/parser.dart';
@@ skipping 109 matching lines @@
       }
     }
 
     errorListener.throwIfErrors();
 
     // Format it.
     var visitor = new SourceVisitor(this, lineInfo, source);
     return visitor.run(node);
   }
 }