title: Rotate matrix so Up vector equals another vector
body: <p>I want to orient my matrix so that the Up vector it facing the same direction as another vector. The orientation of the Forward and Right vectors do not matter.</p>
  
  <p>For example:</p>
  
  <pre><code>matrix4 m; // m.Up = 0, 1, 0
  vector3 v = V3(1,0,0);
  
  // Then I think I have to get the rotation from m.Up and v
  // And then rotate the matrix accordingly
  </code></pre>
  
  <p>But I don't know how todo this and I may be wrong.</p>