title: UISlider using Auto Layout won't resize
body: <p>I am using Constraints in XCODE and I have a Slider in between a few buttons on my interface however whenever I try to "Pin" my Sliders leading and trailing spacing to the superview it never works. I need the slider to scale according to the left and right edges up my view but nothing works. Any idea or does anybody know something I don't about UISliders in Auto-Layout?! <img src="https://i.stack.imgur.com/q6Y0Q.png" alt="Before Scale - you can see the leading / trailing lines"></p>
  
  <p><img src="https://i.stack.imgur.com/sHPIl.png" alt="Then it fails, everytime."></p>