[solverfactory] Using "iterations" or "n" is a bit misleading for SeqILU/SeqILUn
The integer parameter for ILUn is something completely different from the one passed to Se(Jac|SOR|SSOR). It is the levels
of fill-in. Maybe we should change the name used for the ini-files?
SeqILUn expects "iterations" while SeqILU expects "n" as name for the levels of iterations. That seems inconsistent and confusing.