add an result indicator in ui / element steps group

While working on our local project we found sometimes it needs an indicator about the result of user's last step. thus I added a result indicator which can be used to show it. example:

![2013-10-26 11 07 08](https://f.cloud.github.com/assets/2672307/1412776/c3ae5c78-3deb-11e3-96db-33e2c03422a2.png)

sample usage:

    <div class="ui.steps">
      <div class="ui.step"> step 1 </div>
      <div class="ui.state"> or </div>
      <div class="ui.step"> step 2 </div>
    </div>