title: Use transparent stroke color with chartjs pie chart
body: <p>Following the <a href="http://www.chartjs.org/docs/#doughnut-pie-chart-chart-options" rel="nofollow">chart.js docs</a>, I try to draw a transparent stroke line in a pie chart:</p>
  
  <pre><code>var options = { segmentStrokeColor: "rgba(255,255,255,0)" };
  </code></pre>
  
  <p>or </p>
  
  <pre><code>var options = { segmentStrokeColor: "transparent" };
  </code></pre>
  
  <p>But the stroke line is not drawn with these values. Of course it works if I use any other color.</p>