Added code generator setup (taken from Library/Executable_Rat.thy, also works for old code generator).
Added code generator setup (taken from Library/Executable_Rat.thy,
also works for old code generator).

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