41C/CV root finders

[Ángel Martin]

With the new initial estimation there's a marginal improvement - two iteration less if compared against e-8, or just one less if using the e-9 criteria.

It occured to me the reason for the larger number of loops could be that I check for f(i)/f '(i) to meet that criteria, and not for f(i) alone. This is more demanding when f '(i)<1, as the quotient would be larger than the numerator and thus a bit counterproductive...