* 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
* Async RPC
* Limiting number of transactions in queue
* Fixing tests
* Bumping serde and jsonrpc-core
* serde updated to 0.8
* fixed failing tests
* Bumping ipc server
* Fixing API for endpoints
* Experimenting with tests without --release mode