identicon integration for twitter + fixing missing social icons for registration page

public/templates/register.tpl

@@ -11,9 +11,9 @@
 	<div class="well span6 {alternate_logins:display}">
 		<h4>Alternative Registration</h4>
 		<ul class="alt-logins">
-			<li data-url="/auth/twitter" class="twitter {twitter:display}"></li>
+			<li data-url="/auth/twitter" class="twitter {twitter:display}"><i class="icon-twitter-sign icon-3x"></i></li>
-			<li data-url="/auth/google" class="google {google:display}"></li>
+			<li data-url="/auth/google" class="google {google:display}"><i class="icon-google-plus-sign icon-3x"></i></li>
-			<li data-url="/auth/facebook" class="facebook {facebook:display}"></li>
+			<li data-url="/auth/facebook" class="facebook {facebook:display}"><i class="icon-facebook-sign icon-3x"></i></li>
 		</ul>
 	</div>
 </div>

src/user.js

@@ -330,16 +330,12 @@ var utils = require('./../public/src/utils.js'),
 	};
 
 	User.createGravatarURLFromEmail = function(email) {
-		if(email) {
+		if (!email) email = utils.generateUUID();
 		var md5sum = crypto.createHash('md5');
-			md5sum.update((email || '').toLowerCase());
+		md5sum.update(email).toLowerCase().trim();
 		var gravatarURL = 'http://www.gravatar.com/avatar/' + md5sum.digest('hex');
 		return gravatarURL;
 	}
-		else {
-			return "http://www.gravatar.com/avatar/d41d8cd98f00b204e9800998ecf8427e";	
-		}
-	}
 
 	User.hashPassword = function(password, callback) {
 		if(!password) {