title: highcharts add yAxis label based on negative/positive value
body: <p>I have a column chart that shows the trade balance between the US and other countries over time.  </p>
  
  <p>I need the ability to show on the right side of the chart that positive numbers are imports (positive trade balance) and that negative numbers are exports (negative trade balance).</p>
  
  <p>A badly written start can be seen in this <a href="http://jsfiddle.net/0s17qt56/" rel="nofollow">fiddle</a></p>
  
  <p>I'm attempting to add the import/export labels with the following (ugly) code:</p>
  
  <pre><code> yAxis: [{
  
          title: {
              text: 'Millions of Dollars'
          }
      },{
          opposite: true,
          title : {
            rotation: 0,
            text: 'Imports',
            x: 17,
            y: -48
        }
      },{
        opposite: true,
          title : {
            rotation: 0,
            text: 'Exports',
            x: -40,
            y : 5
        }
      }]
  </code></pre>
  
  <p>I'm looking to create something like a category on the yAxis for positive and negative values to label positive values as imports and negative values as exports.</p>
  
  <p>Would like to keep in highcharts so all the nice options that come with highcharts (download, etc) shows this secondary yAxis labels as well.</p>
  
  <p>Is there something simple I'm missing to make this work?</p>
  
  <p>Thanks!!</p>