Estimate gas for contract deployment

I created a smol bash script that calculates the contract deployment cost based on current gas cost. It's PRed into the gakonst/dapptools-template repo but I was wondering if you would want it part of the dapp suite.

It could be particularly sweet to see the cost estimation for different tests during `dapp test`, as it outputs the gas already. This could give the dev a quick overview of how expensive a particular operation will be to the user.

PR: https://github.com/gakonst/dapptools-template/pull/11#issuecomment-917391978
Dependencies: jq, tput, column