- Added some cleanup code

Removed backup_dir_mount_cmd option from Sysstem > server config. The option has been replaced by a script /usr/local/ispconfig/server/scripts/backup_dir_mount.sh. If this script exists, is exacutable and is owned by the root user, then it will be executed upfront of the backup jobs when the option "Backup directory is a mount?" is enabled in server config settings.

this also fixes a problem with ignored vhost subdomains on validation

- adjusted PHP settings regex to allow |, (, and ) (like in "error_reporting = E_ALL & ~(E_NOTICE | E_DEPRECATED | E_STRICT)")

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

- autoselect password if you use "Generate Password" function (saves a click if you want to copy the password).

- Make sure ISPConfig shows the correct error message (instad of an SQL error) when a website is renamed after an alias domain that still exists.
- It should be possible to create two websites with the same domain on the same server as long as the IP differs. I therefore changed the serverdomain index of the web_domain table to include the IP address.

- Fixed "no_domain_perm" error when trying to add proxy directives for subdomains or alias domains (nginx).