add int_of_nat versions of lemmas about int::nat=>int
add int_of_nat versions of lemmas about int::nat=>int

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle