Since truncation works properly now, this hack is no longer necessary;
it actually does more harm than good

Made possible by 1e279e0c5f62ca42a9c65bf739b3f96467a04ece

x/|x| is only a problem if x == 0
just divide by |x|, no matter what non-zero value it is

Bisection will run for ages otherwise

This happens for mu = 0 e.g.

Also rename some parset options

Mostly heap -> stack