Create an interface to ease import into other projects

[julien-h2]

Story

As a user who want to use the Chi token in my own solidity contracts, I want to be able to import the interface of the Chi token directly from Github so that I don't have to manually create it (and risk making a silly mistake).

How to fix

Create the file contracts/IChiToken.sol with the interface of the ChiToken.

EDIT: Uniswap did this and it's very convenient:

wget -nc https://raw.githubusercontent.com/Uniswap/uniswap-v2-core/master/contracts/interfaces/IUniswapV2Pair.sol