title: Getting hue from UIColor yields wrong result
body: <p>I'm doing the following in order to retrieve the <code>hue</code> from a <code>UIColor()</code>:</p>
  
  <pre><code>let rgbColour = UIColor(red: 1.0, green: 0.0, blue: 0.0, alpha: 1.0)
  var hue: CGFloat = 0
  var saturation: CGFloat = 0
  var brightness: CGFloat = 0
  var alpha: CGFloat = 0
  rgbColour.getHue(&amp;hue, saturation: &amp;saturation, brightness: &amp;brightness, alpha: &amp;alpha)
  
  println("\(hue),\(saturation),\(brightness)")
  </code></pre>
  
  <p><strong>Output:</strong></p>
  
  <p><code>1.0,1.0,1.0</code></p>
  
  <p>According to this <a href="http://www.workwithcolor.com/color-converter-01.htm" rel="noreferrer">link</a>, I'm meant to be getting <code>0.0,1.0,1.0</code> for RGB (red) <code>1.0,0.0,0.0</code>.</p>
  
  <p>Am I doing something wrong?</p>