monitor: enhanced the apache-check -> noe we also check if apache was able to send data and not only to establish a connection

The "old" monitoring-module and the "new" rescue-module needed some function twice. So i created a tool-object containing these functions

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

- replace double-quotes with single-quotes whenever appropriate

- reword some output
- fix typos

Fixed: FS#1229 - ISPConfig3 creates the desired e-mail domain twice (on master server AND on the selected Slave) 

- 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.

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Fixed general utf8 encoding problems when data is passed from frontend to server, this fixes also bug FS#1065 - Special characters in autoresponder subject may break the autoresponder 

Added a missing language string in server config form.

- fixed a php notice in app.inc.php