Add ability to preview demo themes in spartacus.

lang/UTF-8/serendipity_lang_da.inc.php

@@ -1096,3 +1096,4 @@
 @define('START_UPDATE', 'Starting Update ...');
 @define('UPDATE_ALL', 'Update All');
 @define('JS_FAILURE', 'The Serendipity JavaScript-library could not be loaded. This can happen due to PHP or Plugin errors, or even a malformed browser cache. To check the exact error please open <a href="%1$s">%1$s</a> manually in your browser and check for error messages.');
+@define('THEMES_PREVIEW_BLOG', 'See demo on blog.s9y.org');