Icons broke down with 2.0.2

Created by: peshi

refer to http://twitter.github.com/bootstrap/base-css.html#icons Email address input example.

   <form>
    <div class="control-group">
      <label class="control-label" for="inputIcon">Email address</label>
      <div class="controls">
        <div class="input-prepend">
          <span class="add-on"><i class="icon-envelope"></i></span>
          <input class="span2" id="inputIcon" type="text">
        </div>
      </div>
    </div>
  </form>