Roll Observatory packages and add a roll script

packages/package_config/lib/src/util.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.
 
 /// Utility methods used by more than one library in the package.
 library package_config.util;
 
 import "package:charcode/ascii.dart";
 
 // All ASCII characters that are valid in a package name, with space
@@ skipping 77 matching lines @@
     var badChar = "U+" + badCharCode.toRadixString(16).padLeft(4, '0');
     if (badCharCode >= 0x20 && badCharCode <= 0x7e) {
       // Printable character.
       badChar = "'${packageName[badIndex]}' ($badChar)";
     }
     throw new ArgumentError.value(packageUri, "packageUri",
         "Package names must not contain $badChar");
   }
   return packageName;
 }