title: regex uppercase to lowercase
body: <p>Is it possible to transform regexp pattern match to lowercase?</p>
  
  <pre><code>var pattern:RegExp;
  var str:String = "HI guys";
  pattern = /([A-Z]+)/g;
  str = str.replace(pattern, thisShouldBeLowerCase);
  </code></pre>
  
  <p>Output should look like this: "hi guys"</p>