title: Centered axis using ShinobiCharts (iOS)
body: <p>I followed the Quick Start tutorial about Shinobicharts, and I'm wondering how to get a centered graph like this one 
  <a href="http://www.noelshack.com/2016-25-1466968639-img-8081.png" rel="nofollow">cos graph</a></p>
  
  <p>I succeded to center the x axis using this :</p>
  
  <pre><code>chart.xAxis.axisPositionValue = @0;
  </code></pre>
  
  <p>How can I center the y axis as well? Thanks in advance!</p>