title: Remove all data from c3js chart
body: <p>How all data can be removed from chart without pointing the names of the data-sets?
  I can't use that way because my data that is populated in the chart is dynamically created.
  This is the way of removing by pointing the data-set name:</p>
  
  <pre><code>chart.unload({
      ids: ['data1', 'data2']                             
  });
  </code></pre>
  
  <p>There is command that removes all of the data? Or i need to recreate the whole chart?</p>