title: I can't set UINavigationBar's barTintColor to clearColor successfully
body: <p>There's a strange iOS 7 thing about UINavigationBar. If you try to set it's <code>barTintColor</code> property to <code>[UIColor clearColor]</code> or any color with a alpha = 0, it totally ignores that value. So for instance, if you write:</p>
  
  <pre><code>[[navigationBar setBarTintColor:[UIColor clearColor]];
  </code></pre>
  
  <p>It doesn't respect the "clear" part at all. Same result with <code>colorWithRed:green:blue:alpha</code>.</p>
  
  <p>But the most interesting part is, if you set <code>translucent</code> property to <code>NO</code>, then it will take the color you specified BUT with alpha 1. So if I specify <code>colorWithRed:1 green:0 blue:0 alpha:0</code> it will be set to pure red with alpha as 1.</p>
  
  <p>How can I achieve it? Is there any possible solution to make it a completely invisible <code>barTintColor</code>, although it requires hacky methods?</p>