title: No readyReadStandardOutput signal from QProcess
body: <p>Why do I never get the readyReadStandardOutput signal when I run the following?</p>
  
  <pre><code>import os, sys, textwrap
  
  from PyQt4 import QtGui, QtCore
  
  out_file = open("sleep_loop.py", 'w')
  out_file.write(textwrap.dedent("""
      import time
  
      while True:
          print "sleeping..."
          time.sleep(1)"""))
  out_file.close()
  
  def started():
      print "started"
  
  def on_error(error):
      errors = ["Failed to start", "Crashed", "Timedout", "Read error", 
                "Write Error", "Unknown Error"]
      print "error: ", errors[error]              
  
  def on_state_change(new_state):
      states = ["Not running", "Starting", "Running"]
      print "new state: ", states[new_state]
  
  def on_out():
      print "got out"
  
  proc = QtCore.QProcess()
  sig = QtCore.SIGNAL
  proc.connect(proc, sig("started()"), started)
  proc.connect(proc, sig("error(ProcessError)"), on_error)
  proc.connect(proc, sig("readyReadStandardOutput()"), on_out)
  proc.connect(proc, sig("stateChanged(ProcessState)"), 
               on_state_change)
  proc.start("python sleep_loop.py")
  
  app = QtGui.QApplication(sys.argv)
  widget = QtGui.QWidget()
  widget.show()
  app.exec_()
  
  proc.close()
  </code></pre>