tty.open() returns stream instead of slaveFD

Also is run in its own session.

lib/tty.js

@@ -10,17 +10,26 @@ exports.getColumns = binding.getColumns;
 exports.open = function(path, args) {
   var fds = binding.openpty();
 
-  var masterFD = fds[1];
   var slaveFD = fds[0];
+  var masterFD = fds[1];
 
   var env = { TERM: 'vt100' };
   for (var k in process.env) {
     env[k] = process.env[k];
   }
 
-  child = spawn(path, args, env, [masterFD, masterFD, masterFD]);
+  var stream = require('net').Stream(slaveFD);
+  stream.readable = stream.writable = true;
+  stream.resume();
 
-  return [slaveFD, child];
+
+  child = spawn(path, args, {
+    env: env,
+    customFds: [masterFD, masterFD, masterFD],
+    setuid: true
+  });
+
+  return [stream, child];
 };