It is now possible to put a customized copy of each .master template file into
  /usr/local/ispconfig/server/conf-custom/install/
  to keep manual changes done in this file.
  If existing, these .master files are used on ISPConfig upgrade instead of the provided installer templates.

Implemented: FS#2582 - Add support for SSL bundle certificates (SSLCACertificateFile) in ispconfig apache vhost

Fixed: FS#2378 - $conf['theme'] value in interface/lib/config.inc.php is overwritten (reset to 'default') on update

Implemented: FS#2283 - Add O option to dovecot transport in postfix master.cf so that X-Original-To: header is added.

Merged revisions 3049-3051,3053-3054,3058,3070,3074-3077,3082,3086-3088,3091-3092,3094-3095 from stable branch.

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

- OpenSUSE: check if the line "include /etc/nginx/sites-enabled/*.vhost;" exists in /etc/nginx/nginx.conf before it is inserted (installation).