Remove package root target and support scripts

tools/list_pkg_directories.py

-#!/usr/bin/env python
-# Copyright (c) 2012, 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.
-
-"""Tool for listing the directories under pkg, with their lib directories.
-Used in pkg.gyp. Lists all of the directories in the directory passed in as an
-argument to this script which have a lib subdirectory.
-
-Usage:
-  python tools/list_pkg_directories.py OPTIONS DIRECTORY
-"""
-
-import optparse
-import os
-import sys
-
-def get_options():
-  result = optparse.OptionParser()
-  result.add_option("--exclude",
-      help='A comma-separated list of directory names to exclude.')
-  return result.parse_args()
-
-def main(argv):
-  (options, args) = get_options()
-  directory = args[0]
-  exclude = options.exclude.split(',') if options.exclude else []
-
-  paths = [
-    path + '/lib' for path in os.listdir(directory)
-    if path not in exclude and os.path.isdir(os.path.join(directory, path))
-  ]
-
-  for lib in filter(lambda x: os.path.exists(os.path.join(directory, x)),
-      paths):
-    print '%s/%s' % (directory, lib)
-
-if __name__ == '__main__':
-  sys.exit(main(sys.argv))