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

- Implemented session message system (template modifications pending)
- Updated ISPC SVN version number to 3.0.5

Fixed: FS#2378 - $conf['theme'] value in interface/lib/config.inc.php is overwritten (reset to 'default') on update

1) Added DEVSYSTEM define in config.inc.php.master  defaults to 0
  If set to 1 classes can load as symbolc links, server.php now

2) server.php now resolves its require()ed files with an absolute
   path instead of relative.

config file which caused the restart of daemons to fail.

- replace double-quotes with single-quotes whenever appropriate
- fix indentation

Added the configuration variable $conf['demo_mode'] in the config.inc.php file. It disables the newly introduced demo mode which limits certain actions in the interface part of ispconfig: the demo mode can be used to run the ispconfig interface part as online demo.

- Fix some comments.

- Better default settings for the "Normal" spamfilter policy.

Added a option to debug the language files (show strings that are not contained in the lang file surrounded by #....#)
Fixed: FS#1063 - Missing language variables in shell user options 

See thread: http://www.howtoforge.com/forums/showthread.php?p=216643