Custom scaling support for I256

0.2.6

I256 CoreArith v0.2.6

Bump v0.2.4 to v0.2.5

bump to make the readme have the same version

power, log, root and custom scaling

i128 type fully functional
Custom Scaling for Arithmetic Operations for i128
Power, Logarithm and Root function working for i128

barebones math lib

0.2.1

fixed log code for SoroNum<U256|I256>