title: No img-responsive in Bootstrap 4
body: <p>I just downloaded the source code for Bootstrap 4 alpha 2 and can't find the class <code>img-responsive</code> in it. It exists in Bootstrap 3 source code and I can find it with Notepad++ but in Bootstrap 4s <code>bootstrap.css</code> in <code>dist</code> folder it doesn't exist.</p>
  
  <p>What happend to it??</p>