Improved: FS#2176 - collision between shell/ftp accounts and client accounts named webXX is not checked

Fixed: FS#2176 - collision between shell/ftp accounts and client accounts named webXX is not checked

Extended datalogUpdate and datalogInsert function in mysql library so that insert_data and update_data arguments can be passed as array too.

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

Changed command order in client_add function so that the insertID is executed right after the sql insert query.

- Fixed a database password encryption error in remote API.
- Fixed database add example script.
- Added examply for new query syntax for forwards.

Fixed: FS#1905 - client_add function in remote api adds duplicate user after returining correct dupliate error.

- Added functions to start / stop / restart virtual machines to the remote api.

- Added some default values for nginx in the web_domain_update function of the remote api.
- Fixed a php warning in the updater.

- WebDAV Users: show only domains that run on Apache (because nginx does not have full WebDAV support).

Fixed: PHP notice in tform_actions.inc.php

- Added a new IP validator to the tform library which validates IPv4 and IPv6 addresses.