SEC-7 Negative Value Transactions

[Gustav-Simonsson]

https://github.com/jonasnick/eth-neg-value-tx

https://github.com/ethereum/go-ethereum/blob/develop/vm/vm.go#L675

Related issue: #340

[obscuren]

Partially fixed in: 655e942

WIP arith: #340

[Gustav-Simonsson]

Re-opening since the fixes for this are still WIP. Let's keep it open until we have the relevant types / types validations fully fixed including working tests.

[obscuren]

Even though the fix is not optimal, this issue is fixed