Add support for the node net module.

frog/file_system_node.dart

 // Copyright (c) 2011, 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('file_system_node');
 
 #import('file_system.dart');
 #import('lib/node/node.dart');
+#import('lib/node/fs.dart');
+#import('lib/node/path.dart');
 
 /** File system implementation using nodejs api's (for self-hosted compiler). */
 class NodeFileSystem implements FileSystem {
   void writeString(String outfile, String text) {
     fs.writeFileSync(outfile, text);
   }
 
   String readAll(String filename) {
     return fs.readFileSync(filename, 'utf8');
   }
@@ skipping 55 matching lines @@
         } else if (stat.isFile()) {
           // Try to remove the file.
           fs.unlinkSync(subpath);
         }
       }
     }
 
     fs.rmdirSync(path);
   }
 }