Define behaviour of Chainout for functions without arguments

The Chainout statement had removed functions without arguments, e.g.,
  CF f;
  L F = f;
  Chainout f;
gave F = 1, which differs from the effect by
  repeat id f(x1?,x2?,?a) = f(x1)*f(x2,?a);
Now we define behaviour of Chainout for functions without arguments such
that it does not touch such functions and leaves them as they are, which
gives the same effect as the repeat-id construction does.