title: Refresh a UITextView
body: <p>I want to write some log text in a UITextview. e.g.: x image is loaded, y object created etc. 
  My problem is: the UITextView doesn't refresh after a line is inserted. I think that when the insertion ends all new texts are displayed in the same time.</p>
  
  <pre><code>append = [@"" stringByAppendingFormat:@"\n%@ file is dowloading...", refreshName]
  logTextView.text = [logTextView.text stringByAppendingString: append];
  </code></pre>
  
  <p>After download I save the file and </p>
  
  <pre><code>append = [@"" stringByAppendingFormat:@"\n%@ file saved", refreshName];
  logTextView.text = [logTextView.text stringByAppendingString: append];
  </code></pre>
  
  <p>I tried</p>
  
  <pre><code>[logTextView setNeedsDisplay]
  </code></pre>
  
  <p>or </p>
  
  <pre><code>[logTextView performSelectorOnMainThread:@selector(setNeedsDisplay) withObject:nil waitUntilDone:YES];
  </code></pre>
  
  <p>but it didn't work :(</p>
  
  <p>Session would be:</p>
  
  <ol>
  <li>Insert new line to textview (downloading)</li>
  <li>Show this text</li>
  <li>Download file (few seconds)</li>
  <li>Insert new line to the UITextView (download finished) </li>
  <li>Show the text</li>
  </ol>
  
  <p>What it happens is:</p>
  
  <ol>
  <li>Download the file (few sec.)</li>
  <li>UITextView show lines (downloadig, download finished)</li>
  </ol>