log function missing

[Saadies]

Hi,

Can you add a log function to be used with Big numbers?

I want to calculate the "level" from a given experience value as in:
XP: 10 -> Level 1
XP: 20 -> Level 2
XP: 40 -> Level 3
...
XP: 1e520 -> Level 5400 (just an example)

For that I would calculate it like this:
log(XP/ lvlBaseCost) / log(lvlCostRate)

For now I can just get the float from (XP / lvlBaseCost) since I won't hit the limit anytime soon but I think that potentially that should be added to this libarary.

Thank you for your work and kind regards

Karim