Using a better approximation

[xmodar]

The implemented method doesn't approximate the function really well. One might consider using this implementation instead. We are working on the log scale to avoid overflow issues. Sorry, I am too lazy to create a pull request 😅

[howion]

Hi, thank you very much for the implementation. I didn't realize this library was being used. So, after reading and testing the given implementation, I did add the implementation as the default. For the previous iterated implementation which is no longer the default, I have added the support for values less than E.