Roll Observatory packages and add a roll script

packages/glob/lib/glob.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 glob;
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:path/path.dart' as p;
@@ skipping 159 matching lines @@
     return null;
   }
 
   Iterable<Match> allMatches(String path, [int start = 0]) {
     var match = matchAsPrefix(path, start);
     return match == null ? [] : [match];
   }
 
   String toString() => pattern;
 }