title: QTimer/Python: Count seconds from start to stop
body: <p>My UI (Qt Designer) has a "Start"-button, a "Stop"-button and a lcdNumber, which should display the seconds between clicking "Start" and "Stop". 
  I followed the instructions there: <a href="https://stackoverflow.com/questions/12661211/cant-seem-to-get-pyqt-countdown-timer-to-work">Can&#39;t seem to get pyqt countdown timer to work</a></p>
  
  <p>But my <code>timeout</code> isn't working, although <code>connect</code> was proposed to me while writing that line: QtCore.QTimer.timeout.connect(self.tick_timer) AttributeError: 'PyQt4.QtCore.pyqtSignal' object has no attribute 'connect'</p>
  
  <p>I also tried to implement lines like that (<code>QtCore.QTimer.connect(QtCore.QTimer(), QtCore.SIGNAL("timeout()"), self, QtCore.SLOT("func()"))</code>) in my update_timer function, but this causes errors (Object::connect: No such slot MainWindow::func()
  Object::connect:  (receiver name: 'MainWindow')) and I don't really understand how to use the connect signal with timeout. </p>
  
  <p>If I comment this "timeout"-line out, the MainWindow appears, but clicking the "Start"-button obviously runs the "tick_timer" function only once, because the lcd-display shows 0:01.</p>
  
  <p>Thanks for your help!</p>
  
  <pre><code>from PyQt4 import QtCore, QtGui, uic
  
  class MainWindow(QtGui.QMainWindow):
  
      def __init__(self, parent=None):
          super(MainWindow, self).__init__(parent)
          uic.loadUi('MainWindow.ui', self)
          # Buttons
          self.QStartButton.clicked.connect(self.start_timer)
          self.QStopButton.clicked.connect(self.stop_timer)
          # Timer
          QtCore.QTimer.timeout.connect(self.tick_timer)
  
      def start_timer(self):
          self.now = 0
          self.tick_timer()
          QtCore.QTimer.start
  
      def update_timer(self):
          self.runtime = "%d:%02d" % (self.now/60,self.now % 60)
          self.lcdNumber.display(self.runtime)
  
      def tick_timer(self):
          self.now += 1
          self.update_timer()
  
      def stop_timer(self):
          QtCore.QTimer.stop
  </code></pre>