title: Foundation button mixin throws error
body: <p>I'm trying to use the Foundation <code>button()</code> mixin in order to change the color of the button. I tried following the example in the docs:</p>
  
  <pre><code>@include button(
  // $padding - Used to build padding for buttons Default: $button-med or rem-calc(12)
  $padding,
  // Background color. We can set $bg:false for a transparent background. Default: $primary-color.
  $bg,
  // If true, set to button radius which is $global-radius or explicitly set radius amount in px (ex. $radius:10px). Default:false.
  $radius,
  // We can set $full-width:true to remove side padding extend width. Default:false
  $full-width,
  // We can set $disabled:true to create a disabled transparent button. Default:false
  $disabled
  );
  </code></pre>
  
  <p>But my compiler complains that the mixin only takes 4 arguments. I can feed in four arguments, but none of them take the action I'd expect.</p>