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