title: Python Scapy gnuplot issue
body: <p>I'm trying to draw a image from scapy as visual result of a particular scan. </p>
  
  <p>This is what I've done: </p>
  
  <pre><code>[1]: a,b=sr(IP(dst="target")/TCP(sport=[RandShort()]*1000))
  [2]: a.plot(lambda x:x[1].id)
  </code></pre>
  
  <p>I'm getting the following response but not graphic image although I have all gnuplot libraries installed properly. I mean when I'm starting scapy I'm not getting any complains about gnuplot or such. </p>
  
  <pre><code>&lt;Gnuplot._Gnuplot.Gnuplot instance at 0x4f244d0&gt;
  </code></pre>
  
  <p>So, how can I see actually the generated image?</p>