title: Can't stick view to bottom using autolayout
body: <p>I have a single view in an xib (no view controller). I've added a small subview (UIView) at the bottom and set a constraint "Bottom space to superview" = 0. There are no other objects or constraints. I expected this view to "stick" to the bottom of the superview but when I view it on iPhone 6, iPhone 5, iPhone 4S, etc. the view doesn't stick but grows beyond the bottom of the screen.</p>
  
  <p>I did the same thing using a UIButton and it works fine.</p>
  
  <p>Thoughts?</p>