title: Why are the buttons inside the UIView squashed to the top?
body: <p>I have installed the <code>ABVideoRangeSlider</code> pod into my project,
  it all works fine besides that the start, end and progress sliders are squashed to the top.
  Here's my code:</p>
  
  <pre class="lang-swift prettyprint-override"><code>import Foundation
  import AVFoundation
  import UIKit
  import Photos
  import AVKit
  import ABVideoRangeSlider
  
  class SliderTest: UIViewController, ABVideoRangeSliderDelegate {
  
      var url: URL?
      var rangeSlider: ABVideoRangeSlider!
  
      let rangeView: UIView = {
          let view = UIView()
          view.backgroundColor = .systemRed
          return view
      }()
  
      override func viewDidLoad() {
          super.viewDidLoad()
  
          AppUtility.lockOrientation(.portrait)
          view.backgroundColor = .lightText
  
          self.rangeSlider = ABVideoRangeSlider()
          rangeView.addSubview(rangeSlider)
  
          self.view.addSubview(rangeView)
          view.bringSubviewToFront(rangeView)
          rangeView.bringSubviewToFront(rangeSlider)
          rangeView.translatesAutoresizingMaskIntoConstraints = false
          self.rangeView.anchor(top: nil, left: view.leftAnchor, bottom: view.bottomAnchor,
                                right: view.rightAnchor, paddingTop: 0, paddingLeft: 20, paddingBottom: 20, paddingRight: 20, width: 0, height: 40)
          self.rangeSlider.delegate = self
          rangeSlider.frame = CGRect(x: 0, y: 0, width: 40, height: 40)
          rangeSlider.centerXAnchor.constraint(equalToSystemSpacingAfter: rangeView.centerXAnchor, multiplier: 1).isActive = true
          rangeSlider.centerYAnchor.constraint(equalToSystemSpacingBelow: rangeView.centerYAnchor, multiplier: 1).isActive = true
          rangeSlider.widthAnchor.constraint(equalToConstant: 200).isActive = true
          rangeSlider.heightAnchor.constraint(equalToConstant: 40).isActive = true
          rangeSlider.translatesAutoresizingMaskIntoConstraints = false
          rangeSlider.contentMode = .scaleToFill
          rangeSlider.clipsToBounds = false
          rangeSlider.autoresizesSubviews = true
          rangeSlider.clearsContextBeforeDrawing = true
          rangeSlider.isOpaque = true
          rangeSlider.semanticContentAttribute = .unspecified
          rangeSlider.isUserInteractionEnabled = true
  
          self.rangeSlider.setVideoURL(videoURL: url!)
          self.rangeSlider.minSpace = 5.0
          self.rangeSlider.maxSpace = 30.0
          self.rangeSlider.setStartPosition(seconds: 0.0)
          self.rangeSlider.setEndPosition(seconds: 30.0)
          self.rangeSlider.updateProgressIndicator(seconds: 0.0)
          self.rangeSlider.updateThumbnails()
      }
  
  
      func didChangeValue(videoRangeSlider: ABVideoRangeSlider, startTime: Float64, endTime: Float64) {
          print(startTime)    // Prints the position of the Start indicator in seconds
          print(endTime)      // Prints the position of the End indicator in seconds
      }
  
      func indicatorDidChangePosition(videoRangeSlider: ABVideoRangeSlider, position: Float64) {
          print(position)      // Prints the position of the Progress indicator in seconds
      }
  }
  </code></pre>
  
  <p>I've also downloaded the example project to see what's wrong, but I don't know why
  what's the problem.</p>
  
  <p>My project:</p>
  
  <p><a href="https://i.stack.imgur.com/P9OJ2.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/P9OJ2.png" alt="enter image description here"></a></p>
  
  <p>example project:</p>
  
  <p><a href="https://i.stack.imgur.com/PYfHp.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/PYfHp.png" alt="enter image description here"></a></p>
  
  <p>example code:</p>
  
  <p><a href="https://i.stack.imgur.com/zkqUR.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/zkqUR.png" alt="enter image description here"></a></p>
  
  <pre class="lang-swift prettyprint-override"><code>import UIKit
  import ABVideoRangeSlider
  import AVKit
  import AVFoundation
  
  class ViewController: UIViewController, ABVideoRangeSliderDelegate {
  
      @IBOutlet var videoRangeSlider: ABVideoRangeSlider!
      @IBOutlet var playerView: UIView!
      @IBOutlet var lblStart: UILabel!
      @IBOutlet var lblEnd: UILabel!
      @IBOutlet var lblMinSpace: UILabel!
  
      let path = Bundle.main.path(forResource: "test", ofType:"mp4")
  
      override func viewDidLoad() {
          super.viewDidLoad()
      }
  
      @IBAction func playVideo(_ sender: Any) {
          let player = AVPlayer(url: URL(fileURLWithPath: path!))
          let playerViewController = AVPlayerViewController()
          playerViewController.player = player
          self.present(playerViewController, animated: true) {
              playerViewController.player!.play()
          }
      }
  
      override func viewWillAppear(_ animated: Bool) {
          videoRangeSlider.setVideoURL(videoURL: URL(fileURLWithPath: path!))
          videoRangeSlider.delegate = self
          videoRangeSlider.minSpace = 60.0
          //        videoRangeSlider.maxSpace = 180.0
  
          lblMinSpace.text = "\(videoRangeSlider.minSpace)"
  
          // Set initial position of Start Indicator
          videoRangeSlider.setStartPosition(seconds: 50.0)
  
          // Set initial position of End Indicator
          videoRangeSlider.setEndPosition(seconds: 150.0)
      }
  
      // MARK: ABVideoRangeSlider Delegate - Returns time in seconds
      func didChangeValue(videoRangeSlider: ABVideoRangeSlider, startTime: Float64, endTime: Float64) {
          lblStart.text = "\(startTime)"
          lblEnd.text = "\(endTime)"
      }
  
      func indicatorDidChangePosition(videoRangeSlider: ABVideoRangeSlider, position: Float64) {
          print("position of indicator: \(position)")
      }
  }
  </code></pre>