Improve demo page

1. add link back to GitHub repo on demo page
2. remove jQuery in demo page

Author: imcotton

demo/index.html

@@ -4,7 +4,6 @@
         <meta charset="utf-8">
         <title>AngularJS ui-mask</title>
 
-        <script src="https://code.jquery.com/jquery-2.1.4.min.js"></script>
         <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.4.1/angular.js"></script>
         <link rel="stylesheet" href="https://netdna.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.css">
 
@@ -19,7 +18,9 @@
         </script>
         <section id="mask">
             <div class="page-header">
-                <h1>Mask</h1>
+                <h1>Mask
+                    <small><a href="https://github.com/angular-ui/ui-mask">GitHub</a></small>
+                </h1>
             </div>
             <div class="row">
                 <div class="col-md-6">