title: Creating rotation matrix
body: <p>I need to create a rotation function that will be used to rotate items around, it nearly works apart from when trying to do -sin.
  There doesnt seem to be a function that allows this.</p>
  
  <p><img src="https://i.stack.imgur.com/JdCuT.png" alt="Rotation matrix"></p>
  
  <pre><code>Matrix.createRotation = function (rotation) {
  
      return new Matrix(Math.cos(rotation),  Math.sin(rotation), 0,
          Math.sin(rotation), Math.cos(rotation), 0, 0, 0, 1);
  };
  </code></pre>