title: Append to beginning of NSString method
body: <p>I would like to append NSString <code>A</code> in front of NSString <code>B</code>. Is there a built in method to append to the beginning of a NSString instead of the end of the NSString?</p>
  
  <p>I know that I can use <code>stringWithFormat</code>, but then what is the difference between using <code>stringWithFormat</code> and <code>stringByAppendingString</code> to add text to the end of a NSString? </p>