* fix modexp bug: return 0 if base=0 (#6424)
* Running state test using parity-evm (#6355)
* Initial version of state tests.
* Refactor state to support tracing.
* Unify TransactResult.
* Add test.
* Byzantium updates
* Add info on forks.
* Add new registry ABI
* Import registry2 & fix exports
* Select ABI based on code hash
* Render new event types (owner not available)
* New registry.
* Rename old chain.
* Fix test.
* Another fix.
* Finish rename.