Merged revisons 3687-3748 from 3.0.5 stable branch.
Implemented FS#2593 - PHP Warning: chmod(): No such file or directory in /root/ispconfig3_install/install/dist/lib/debian60.lib.php
Implemented FS#2595 - postfix RSA certificate generation.
 - Postfix SSL Key is now 4096 bit for greater security
Merged revisions 3753-3756 from 3.0.5 stable branch.
FS#2615 - Fix up ufw installation code
  - This makes ufw the default if it's found
Merged revisions from 3.0.5 stable branch: 3758-3768, 3769 shall not be merged to trunk.
Implemented checkboxes in Interface Config to enable showing/hiding the tabs Mail Filters, Autoresponders and Custom Rules for mailboxes.

See also http://www.howtoforge.com/forums/showthread.php?t=59539
- Added: path to sendmail in server config (prepared for mailsafe module)
Merged Revisions 3771-3801 from stable branch.
Merged revisions 3803-3844 from stable branch.
Silly Microsoft line endings removed to not error on Linux Subversion servers...
FS#2758 - Misspelled word on front end