Lost on master(!866) ... now on cherry-picked on !1132

- Fixed password length in lost password function

- Added warning in the interface when a path for a shelluser is set that is outside of the website docroot.
- Added security settings feature to allow the root user of a server to control most aspects of whet the admin user of the controlpanel is allowed to do in system settings. This is especially useful for managed severs where the ispconfig admin user and the root user of the server are different persons.

Fixed: reseller has_clients if limit_client is != 0, e.g. -1 or > 0. Thanks to Sergio for pointing out this issue.

Fixed/Implemented: replaced intval() by $app->functions->intval() in all interface functions due to big number problem in intval()

- Fixed {RECORDID} placeholder in SQL datasource strings.

- Changed shell of website linux user to /bin/false

Added a helper script for updates from SVN.

Added a server module for clients and a mail plugin.