title: C3JS bar chart with specific order
body: <p>If I have a C3JS grouped bar chart defined like the following, how can I get the segments to stay in the order I've defined them instead of in ascending order by value?  By default C3 will order them as 5, 10, 40, but I want it to remain as 10, 40, 5.</p>
  
  <pre><code>c3.generate({
    bindto: '.active-loads',
    data: {
      columns: [
        ['Picking up future', 10],
        ['Enroute', 40],
        ['Delivered', 5]
      ],
      type: 'bar',
      groups: [
        ['Picking up future', 'Enroute', 'Delivered']
      ],
      onclick: function(d) {
        console.debug(d);
      }
    },
    axis: {
      rotated: true,
      x: {
        show: false
      }
    }
  });
  </code></pre>
  
  <p><strong>EDIT</strong></p>
  
  <p>Turns out it's as easy as specifying <code>order: null</code> in the <code>data</code> property.</p>