generate multiple csv files as output since the plots for each would have to be handled separately anyway, and to avoid mixing families of data in a single csv.
test case in the vein of PR #165
if max-mols is too low, then the code throws an error because auc/roc curves cannot be created for a single category.
Some additional things to think about:
max-molsis too low, then the code throws an error because auc/roc curves cannot be created for a single category.