add amavis-configfile-location for centos 6.4; add amavis-initscrip-name for centos 6.4; fixed missing private_key in mail/mail_domain_dkim_create.php

display dns-record for dkim in the mail-domain
rewrite function domain_dkim_update in server/plugins-available/mail_plugin_dkim.inc.php
change dns*.php according to commit 604c0c24

skip writing dkim-values for inactive domains
removed the public-dkim-key from the interface
added german language-file

- Added dkim installation to installer.
- Added backup filesize in backup cronjob.

Reverted SVN trunk back to revision 3938 to remove changes in default theme an a replacement of the ispconfig logo.