Task 3: Gwei vs Decimal feature

[icmoore]

At the moment, all values are presented as decimal by default. Since some users of the tool will be Solidity Devs, DeFiPy should have the ability to present outcomes in either Gwei (ie, 1x10^18) or Decimal as a feature.

Completion of this task would be blocked by Task 2, as mpmath would need to be implemented first before addressing this issue.

[icmoore]

This is currently working for Uniswap V2 / V3