show line where contract call failed

[snd]

if a contract call or deploy fails (due to revert, out of gas, etc) show the actual source line on which the failure occurred.

this would greatly improve the experience of writing and debugging tests!

truffle doesn't have this feature (yet).

could be extend by also dumping/showing the last known local and storage variables.

this could be a starting point: https://ethereum.stackexchange.com/questions/25479/how-to-map-evm-trace-to-contract-source/26216#26216

[snd]

related to #7