added arithmetic example using div and mod

bump up Nitpick's axiom/definition unfolding limits, because some real-world problems (e.g. from Boogie) ran into the previous limits; the limits are there to prevent infinite recursion; they can be set arbitrarily high without much harm

merged

comment out debugging code in Nitpick

fixed bug in Nitpick's handling of "The" and "Eps" when the return type is a "bool"

made "NitpickHOL.normalized_rhs_of" more robust in the face of locale definitions