Changed Font Awesome email icon to envelope-square

The envelopment-square fits better with the other icons.

share-buttons-font-awesome.html

@@ -7,5 +7,5 @@
 	<li><a href="http://www.reddit.com/submit?url=URL&title=TITLE" target="_blank" title="Submit to Reddit"><i class="fa fa-reddit-square fa-2x"></i></a></li>
 	<li><a href="http://www.linkedin.com/shareArticle?mini=true&url=URL&title=TITLE&summary=BRIEFDESCRIPTION&source=URL" target="_blank" title="Share on LinkedIn"><i class="fa fa-linkedin-square fa-2x"></i></a></li>
 	<li><a href="http://wordpress.com/press-this.php?u=URL&t=TITLE&s=BRIEFDESCRIPTION&i=PREVIEWIMAGEURL" target="_blank" title="Publish on WordPress"><i class="fa fa-wordpress fa-2x"></i></a></li>
-	<li><a href="mailto:?subject=TITLE&body=BRIEFDESCRIPTION: URL" target="_blank" title="Email"><i class="fa fa-envelope fa-2x"></i></a></li>
+	<li><a href="mailto:?subject=TITLE&body=BRIEFDESCRIPTION: URL" target="_blank" title="Email"><i class="fa fa-envelope-square fa-2x"></i></a></li>
 </ul>