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.

Fixed: FS#2593 - PHP Warning: chmod(): No such file or directory in /root/ispconfig3_install/install/dist/lib/debian60.lib.php
Fixed: FS#2595 - postfix RSA certificate generation.
 - Postfix SSL Key is now 4096 bit for greater security

- I had to remove the fail2ban caonfig for now as its incomplete and adds rules for dovecot on courier systems.
It is planned to add a complete fail2ban configuration in one of the next releases.

Merged revisions 1832-1836 from stable (added dovecot support for debian squeeze and added a new distid and class for debian6 specific modifications.