- Fixed FS#2441 - FastCgiExternalServer: redefinition of previously defined class "/usr/lib/cgi-bin/php5-fcgi".

- Added check for the apps vhost to find out if the default PHP-FPM pool uses port 9000 or the socket /var/run/php5-fpm.sock.

- Added overtraffic notifications to traffic quota system (part of FS#2059 - Extend Traffic quota system)

Fixed (partly) FS#2310 - Template switch not working in mailuser module, for dashlets and the login page

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

- 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##").

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