title: Adding vendor prefixes with LESS mixin
body: <p>I'm getting a Syntax Error for this mix-in:</p>
  
  <pre><code>.vendors(@statement){
    @statement;
    -moz-@statement;
    -webkit-@statement;
  }
  </code></pre>
  
  <p>Any way to do this, or do mixin variables have to be on the right side of a <code>:</code>?</p>