title: How does the addEntry method update LineChart in realtime?
body: <p>I'm using the iOS-Charts to display a simple cubic line chart and want to update the chart every second with new data being reported. I've tried using the addEntry method to dynamically add the value to the end of the array and I've verified that the data is indeed successfully added to the array after each second.  However the chart itself does not update.  I've looked at the documentation on the MPAndroidChart and it does not specify calling any kind of update method after first calling the addEntry method.  I do see in another section of the documentation that there is an invalidate() method on the Chart object that 'refreshes' the chart, however, I do not have that option when I access the Chart object, nor do I know if this is required.</p>
  
  <p>Sample Code:</p>
  
  <pre><code>var set1 = lineChartView.data?.getDataSetByIndex(0)
  var index = set1?.entryCount
  var value = arc4random_uniform(14) + 1
  var chartEntry = ChartDataEntry(value: Float(value), xIndex: index!)
  
  set1?.addEntry(chartEntry)
  </code></pre>
  
  <p>In the demo project the charts are modified with a slider control, but within that example it's just recreating the data and resetting the chart.data object, not dynamically modifying the original DataSet as I'm trying to do.</p>
  
  <p>Any help on what I need to do or where I should look is much appreciated.</p>
  
  <p>xcode 6.3</p>
  
  <p>swift 1.2</p>
  
  <p>iOS 8.3</p>
  
  <p>iOS-Charts 2.1.0</p>