shorten links while tweeting, ref #34

index.html

@@ -83,7 +83,7 @@
     Created by <a href="http://gabrielecirulli.com" target="_blank">Gabriele Cirulli.</a> Based on <a href="https://itunes.apple.com/us/app/1024!/id823499224" target="_blank">1024 by Veewo Studio</a> and conceptually similar to <a href="http://asherv.com/threes/" target="_blank">Threes by Asher Vollmer.</a>
     </p>
     <div class="sharing">
-      <a href="https://twitter.com/share" class="twitter-share-button" data-text="Check out 2048, a game where you join numbers to score high! #2048game" data-via="gabrielecirulli">Tweet</a>
+      <a href="https://twitter.com/share" class="twitter-share-button" data-text="Check out 2048, a game where you join numbers to score high! #2048game" data-via="gabrielecirulli" data-url="http://git.io/2048">Tweet</a>
       <script>!function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0],p=/^http:/.test(d.location)?'http':'https';if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src=p+'://platform.twitter.com/widgets.js';fjs.parentNode.insertBefore(js,fjs);}}(document, 'script', 'twitter-wjs');</script>
 
       <form class="pp-donate" action="https://www.paypal.com/cgi-bin/webscr" method="post" target="_blank">

js/html_actuator.js

@@ -156,6 +156,7 @@ HTMLActuator.prototype.scoreTweetButton = function () {
   tweet.classList.add("twitter-share-button");
   tweet.setAttribute("href", "https://twitter.com/share");
   tweet.setAttribute("data-via", "gabrielecirulli");
+  tweet.setAttribute("data-url", "http://git.io/2048");
   tweet.textContent = "Tweet";
 
   var text = "I scored " + this.score + " points at 2048, a game where you " +