title: Enabling/Disabling NSLayoutConstraints in InterfaceBuilder
body: <p><code>NSLayoutConstraint</code> (in <code>iOS 8.0</code>) has a <code>BOOL</code> property called <code>active</code> which makes it easy to disable/enable said layout constraint on-the-fly.</p>
  
  <p>To create a second layout set for a view controller which I can then programmatically enable/disable (via an <code>IBOutletCollection</code> of <code>NSLayoutConstraints</code> for both sets) , I'll need to disable my already defined layout constraints in interface builder. </p>
  
  <p>Let me clear here I do NOT want to delete them, just disable them so that i can design a second set without interface builder complaining all the time about mismatching constraints.
  Furthermore switching size classes is not an option, since the layout sets are meant for one and the same size class.</p>
  
  <p>Is there an option to do so?</p>
  
  <p>Thanks in Advance</p>
  
  <p>Malte</p>
  
  <p>Further Information: <code>SDK Version: 8.1</code> <code>Deployment Target 8.0</code></p>