Fixed: FS#2743 - Check if language merge function adds duplicate backslashes when the source file contains a backslashes

Proposed fix for: FS#2781 - Some remote functions returning NULL instead of affected/deleted elements count

Fixed: FS#2776 - Add new Website make error when System->Server services-> Webserver - disabled and no slave server

Disabled mysql error messages in interface. If a developer needs it, he can enable it in the mysql db lib for debugging.

Fixed a sql error in vm list.

- Added: remoting queries with a lot of results (e.g. email addresses or alias domains or dns rr) lead to non-functioning soap requests
  - added '#OFFSET#' AND '#LIMIT#' handling to the query
  - added automatic 'WHERE 1' if an empty array was given as query
  example: $result = $api->sites_web_domain_get('type' => 'vhost', '#OFFSET#' => 25, '#LIMIT#' => 50); to get the websites 26 to 75

FS#2700 - Delete Addon Package: Invalid ID