preparemoodle.py : ZeroDivisionError with less than 6 lines in Bewertungen.csv
With a Bewertungen.csv with less than 6 lines preparemoodle.py stops at
line 124 if not (cnt % round(numlines/10)):
with a ZeroDivisionError because round(numlines/10) = 0 (numlines <6)
Not really that important, because only happens when testing with a few files.