title: Rotated rectangle bounding box size
body: <p>If I have a given rectangle, with the width <code>w</code>, height <code>h</code> and angle <code>r</code></p>
  
  <p>How large does another rectangle which <em>contains all points of the rotated rectangle</em> need to be?</p>
  
  <p>I would need this to perform fast bounding box checks for a 2D physics engine I am making</p>