Use the new fastest log(2) series

[fredrik-johansson]

As of November 13 there is a new series for log(2) which should be even faster than the one already implemented: https://mathoverflow.net/questions/463436/are-these-fast-convergent-series-for-log2-log3-and-log5-already

[fredrik-johansson]

Apparently there is also a new champion series for zeta(5):
https://mathoverflow.net/questions/486353/a-curious-hypergeometric-series-related-to-riemanns-zeta-function

[fredrik-johansson]

And here are further faster formulas for logarithms of small integers: https://mathoverflow.net/questions/487156/ramanujan-type-identities-for-logp-p-in-mathbbz-2

Note that these are probably not faster than Machin-type formulas for multi-evaluation.