localization of toString methods, especially for exception classes

[dheldt]

I think it might be wise the start localization of the toString methods of the exception classes, especially, if we
use them in the Reporting, which we started to work on. It would easily allow to generate reports in German and English, which is a good idea, I think.

[dheldt]

There was some progress on this, but I fear, something went wrong. I now get exception texts like

Der Dateiname {0} passt zu keiner bekannten Log Message.

so the String.format seems to be broken.