title: Opencv multiply scalar and matrix
body: <p>I have been trying to achieve something which should pretty trivial and is trivial in <em>Matlab</em>.</p>
  
  <p>I want to simply achieve something such as:</p>
  
  <pre><code>cv::Mat sample = [4 5 6; 4 2 5; 1 4 2];
  sample = 5*sample;
  </code></pre>
  
  <p>After which sample should just be:</p>
  
  <pre><code>[20 24 30; 20 10 25; 5 20 10]
  </code></pre>
  
  <p>I have tried <code>scaleAdd</code>, <code>Mul</code>, <code>Multiply</code> and neither allow a scalar multiplier and require a matrix of the same "size and type". In this scenario I could create a Matrix of Ones and then use the scale parameter but that seems so very extraneous</p>
  
  <p>Any direct simple method would be great!</p>