Protect manifest request by CORS to prevent guest sessions.

Author: rxu

styles/all/template/event/overall_header_head_append.html

@@ -14,7 +14,7 @@
 <meta name="application-name" content="{{ SHORT_SITE_NAME }}">
 
 <!-- Link to app's configuration manifest -->
-<link rel="manifest" href="{{ U_MANIFEST_URL }}">
+<link rel="manifest" href="{{ U_MANIFEST_URL }}" crossorigin="">
 
 {% if U_TOUCH_ICON %}
 <!-- App icon for iOS, a fallback to icons defined in the manifest -->