Roll Observatory packages and add a roll script

packages/path/lib/src/parsed_path.dart

 // Copyright (c) 2013, 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 path.parsed_path;
 
 import 'internal_style.dart';
 import 'style.dart';
 
 class ParsedPath {
@@ skipping 163 matching lines @@
     // If there is no dot, or it's the first character, like '.bashrc', it
     // doesn't count.
     if (lastDot <= 0) return [file, ''];
 
     return [file.substring(0, lastDot), file.substring(lastDot)];
   }
 
   ParsedPath clone() => new ParsedPath._(style, root, isRootRelative,
       new List.from(parts), new List.from(separators));
 }