- nginx: merge function: default action is now to replace older locations in the nginx vhost configuration; a merge  instead of a replacement can be achieved by putting the string "##merge##" (without quotes) at the end of the most recent location line (e.g. "location ~ \.php$ { ##merge##").

- Improved support for multiple PHP versions. Additional PHP versions have now their own form and database table.

- Added "actions" framework in server to replace the functions provided by the core modules
- Moved system update function from remoteactins core module to software update plugin.

and make changes to mysql users in the mysql plugin module.

Refs: 1722

Also removed the calls to the db closeConn calls in favor of
destryong the connections on the class __destruct() 's..

Since firebird db had a closeConn as well, changed its __destruct
to calls its own personal closeConn which otherwise left unmodified.

Refs: 1722

- Fixed UTF-8 support in email function.

Fixed: FS#1775 - PHP Fatal error: Call to a member function queryAllRecords() on a non-object in /usr/local/ispconfi

- Installer adds Apache and nginx user to ispapps group.
- Installer makes sure that /var/www/apps has 755 permissions.

- Added PHP-FPM pm settings (pm.max_children, pm.start_servers, pm.min_spare_servers, pm.max_spare_servers) to the "Options" tab of a website.

- Changed FastCGI buffers for ISPConfig nginx vhost because otherwise you get "upstream sent too big header while reading response header from upstream" on OpenSUSE.
- Added 502 error page ("Bad Gateway").
- Added "fastcgi_intercept_errors on;" to nginx vhost template so that ISPConfig's error pages are displayed instead of the default nginx ones.