Bugfix: $app->system->unlink function had wrong parameter name, no files were deleted ever

- Added missing sys_tpl table to ispconfig3.sql and moved the definition of the table to the upd_0035.sql file as new tables cant be added in existing update files.
- added new ssl_key field to web_domain table.
- cleaned up unused code from apache plugin.

- Added new web folder named private to web folder layout. The folder is intended to store data that shall not be visible in the web directory, it is owned by the user of the web.
- Changed ownership of web root directory to root user in all security modes to prevent symlink attacks.
- Apache log files are now owned by user root.
- Improved functions in system library.

Added wrappers for several base filesystem functions like rename, copy, chown, chgrp etc. to system lib.

This option can be enabled under System > Server config and is named "Web folder protection".

- reword some output
- fix typos

- Added alternative code for a is_group function which might perform better then the old implementation. It has to be tested yet and is commented out.

- added installation instructions for opensuse 11.2 with bind and dovecot
- fixed a bug in bind plugin.
- improved opensuse installer.

- Add some functionallity to MySQL class

- improved several functions in site module
- added server classes to restart services