title: formatting value in a string to have a decimal separator
body: <p>if i have a value stored like:</p>
  
  <pre><code>long long unsigned x=1000000000000;
  </code></pre>
  
  <p>i'd like to have a</p>
  
  <pre><code>NSString *strx=[...];
  </code></pre>
  
  <p>so if i use NSLog or bitmapfont for this integer, what is displayed will be:</p>
  
  <pre><code>1,000,000,000,000
  </code></pre>
  
  <p>do exists this king od formatter?
  thanks </p>