title: Accessibility: UISlider's UIControlEventValueChanged is not posted when slider.value is set in Voice-over mode
body: <p>I am having a UISlider in my parent view. 
  I want to honor the Voice-over gestures for slider movement and thus, i have implemented accessibilityIncrement and accessibilityDecrement methods as below:</p>
  
  <pre><code>- (void)accessibilityIncrement
  {
       float finalValue = self.value;
      finalValue = (finalValue + 1);
      if (finalValue &gt; self.maximumValue)
          finalValue = self.maximumValue;
      self.value = finalValue;    
  }
  
  - (void)accessibilityDecrement
  {
      float finalValue = self.value;
      finalValue = (finalValue - 1);
      if (finalValue &lt; self.minimumValue)
          finalValue = self.minimumValue;
      self.value = finalValue;
  
  }
  </code></pre>
  
  <p>The issue is when I set the value of the slider (using self.value = finalValue), the selector for UIControlEventValueChanged event does not get called. Is this a Bug?</p>
  
  <p>Thanks!</p>