Fixed: PHP notices in jailkit user plugin.

- Improved checks in mailbox delete function.

- Improved https detection in  get_ispconfig_url() function.

- Added missing alias address list to sieve filter template.

- Improved error message in client and reseller language file.

- Improved date format in nl language file
- Disabled debugging mode in interface plugin class.

- nginx: changed /awstats-icon location from "location /awstats-icon" to "location ^~ /awstats-icon" so that it isn't affected by any "location ~*  \.(jpg|jpeg|png|gif|css|js|ico)$" directive.

- Added a fix to allow that master and slave database in a multiserver setup can reached on the same mysql hostname.

- nginx: added client_max_body_size 20M; to ISPConfig and apps vhost to allow big uploads; added fastcgi_read_timeout 240; to phpMyAdmin configuration in aapps vhost to allow for longer backend operations (such as importing an SQL dump with lots of InnoDB queries).

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- nginx: Changed fastcgi_param SCRIPT_FILENAME lines in apps.vhost so that phpMyAdmin and SquirrelMail work also with cgi.fix_pathinfo=0.