title: readAll() from QSerialPort doesn't include the last response sent
body: <p>I'm using Qt to control a serial device. If I send a command to my serial device, I do something like <code>serial-&gt;write("command \r\n")</code>. I made a push button which changes the text inside a plain text widget to the response of the serial port. To get the response of the serial port, I'm using <code>serial-&gt;readAll()</code>. The problem is it shows the 2nd to last response rather than the one I was expecting. Does Qt have some sort of buffer which is keeping hold of this response?</p>
  
  <p><strong>EDIT</strong>
  I botched it by using recursion and compared the strings recieved</p>