title: UILabel sizeToFit and constraints
body: <p>Is there any simple way which can help me to change position of dependent views dynamically using their content size?</p>
  
  <p>I want to show several views in column which all have varying content. And I want them to be placed one after another (I've created layout using constraints which looks like this)</p>
  
  <p><img src="https://i.stack.imgur.com/ehmMe.png" alt="initial layout"></p>
  
  <p>But whenever I change content of labels and call <code>sizeToFit</code>, system seems to ignore layout. </p>
  
  <p><img src="https://i.stack.imgur.com/vub1F.png" alt="after size to fit call"></p>
  
  <p>At the moment I'm interested only in height property, I know that constraining rect can be used too and in the past I wrote many categories on UIView to change sizes dynamically (I guess everyone did). But maybe there is a simple way which I don't know?</p>