Introducing Math.log()

Fixes 0.69 ÷ 44.01

Inspired by Wine's JScript interpretor:
https://github.com/wine-mirror/wine/blob/2e752a115ac814fc252af592d01c816b34e96cb0/dlls/jscript/number.c#L468-476

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Fix sigfigs calculation for 0.00001

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Prepare for mocha-based testing framework

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
test

Signed-off-by: Timothy Gu <timothygu99@gmail.com>