HelperReport.konvertiereZeitDezimalInHHMMSS with negative numbers
The output string of HelperReport.konvertiereZeitDezimalInHHMMSS does not have a '-' if the input time is negative and smaller than 1 hour.
The output string of HelperReport.konvertiereZeitDezimalInHHMMSS does not have a '-' if the input time is negative and smaller than 1 hour.