Add support for the node net module.

frog/lib/node/cluster.dart

Index: frog/lib/node/cluster.dart
===================================================================
--- frog/lib/node/cluster.dart	(revision 0)
+++ frog/lib/node/cluster.dart	(revision 0)
@@ -0,0 +1,43 @@
+// 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('cluster');
+#import('node.dart');
+
+// module cluster
+
+/**
+ * Note: cluster.fork will fail when run from frogsh. It will succeed
+ * when dart code is compiled to JavaScript, and the resulting
+ * JavaScript is run from node.js.
+ */
+ 
+typedef void ClusterDeathListener(ChildProcess cp);
+
+class cluster native "require('cluster')" {
+  static void fork() native;
+  static bool isMaster;
+  static bool isWorker;
+  
+  // EventEmitter
+  static void removeAllListeners(String event) native;
+  static void setMaxListeners(num n) native;
+  var _listeners(String key)
+    native "return this.listeners(key);";
+
+  // Death event
+  static void emitDeath(ChildProcess cp)
+    native "this.emit('death', cp);";
+  static void addListenerDeath(ClusterDeathListener listener)
+    native "this.addListener('death', listener);";
+  static void onDeath(ClusterDeathListener listener)
+    native "this.on('death', listener);";
+  static void onceDeath(ClusterDeathListener listener)
+    native "this.once('death', listener);";
+  static void removeListenerDeath(ClusterDeathListener listener)
+    native "this.removeListener('death', listener);";
+  static List<ClusterDeathListener> listenersDeath()
+      => new _NativeListPrimitiveElement<ClusterDeathListener>(_listeners(
+          'death'));
+}