Replace jQuery UI CSS with bootstrap one

Signed-off-by: Michal Čihař <michal@cihar.com>

weblate/html/meta-header.html

 {% load static %}
 {% load url from future %}
 
-  <link rel="stylesheet" type="text/css" href="{% get_media_prefix %}theme/jquery-ui-1.10.3.custom.min.css" />
+  <link rel="stylesheet" type="text/css" href="{% get_media_prefix %}bootstrap/css/bootstrap.min.css" />
+  <link rel="stylesheet" type="text/css" href="{% get_media_prefix %}bootstrap/css/bootstrap-theme.min.css" />
   <link rel="stylesheet" type="text/css" href="{% get_media_prefix %}style.css" />
   <script src="{% get_media_prefix %}js/jquery-2.1.0.min.js" type="text/javascript"></script>
   <script src="{% get_media_prefix %}js/jquery.cookie.js" type="text/javascript"></script>