Changed cron_daily.php to avoid some php notices.

- Added options to use a mounted backup directory. This allows for remote backups, e.g. vis sshfs to a backup server. The backup script checks if the backup directory is mounted, and if not, tries to mount it.

http://www.howtoforge.com/forums/showthread.php?t=62691

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

- Added backup size to web backups

Links removed from sum rows in stats

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

- install: touch auth.log
- login: write success/fail to auth.log
- cron: log rotation for auth.log

- Added "actions" framework in server to replace the functions provided by the core modules
- Moved system update function from remoteactins core module to software update plugin.

- Added SNI config field in sysetm > server config > web.