title: iOS Charts moveViewToX does not seem to work
body: <p>I am trying to move the current displayed data range.  Reading the documents, it seems that I should be able to use <code>moveViewToX</code> function to move the left side of the view to the given x value.</p>
  
  <p>I made a test code that has 1 View with a button.  The graph is displayed correctly when the view loads in simulator.  When the button is clicked, it calls <code>moveViewToX</code>.  However, nothing happens when I click the button (the print text is printed to console when the button is clicked, the graph view remains the same).</p>
  
  <pre><code>import Charts
  import UIKit
  
  class ViewController: UIViewController {
  
  override func viewDidLoad() {
      super.viewDidLoad()
      // Do any additional setup after loading the view, typically from a nib.
  
      //Setup Test Chart
      self.lineChartView.data = LineChartData(dataSet: lineChartDataSet())
  
  }
  
  
  fileprivate func lineChartDataSet() -&gt; LineChartDataSet {
      var dataEntries = [ChartDataEntry]()
      dataEntries.append(ChartDataEntry(x: 1, y: 2))
      dataEntries.append(ChartDataEntry(x: 3, y: 5))
      dataEntries.append(ChartDataEntry(x: 5, y: 10))
      dataEntries.append(ChartDataEntry(x: 6, y: 2))
      dataEntries.append(ChartDataEntry(x: 10, y: 15))
      dataEntries.append(ChartDataEntry(x: 12, y: 7))
      dataEntries.append(ChartDataEntry(x: 20, y: 10))
      dataEntries.append(ChartDataEntry(x: 30, y: 15))
  
      return LineChartDataSet(values: dataEntries, label: "Test Data")
  }
  
  @IBAction func buttonClick(_ sender: UIButton) {
      print("Button clicked")
      self.lineChartView.moveViewToX(5)
  }
  @IBOutlet weak var lineChartView: LineChartView!
  }
  </code></pre>