Byzantium updates (#5855)

* EIP-211 updates

* benchmarks

* blockhash instruction gas cost updated

* More benches

* EIP-684

* EIP-649

* EIP-658

* Updated some tests

* Modexp fixes

* STATICCALL fixes

* Pairing fixes

* More STATICALL fixes

* Use paritytech/bn

* Fixed REVERTing of contract creation

* Fixed more tests

* Fixed more tests

* Blockchain tests

* Enable previously broken tests

* Transition test

* Updated tests

* Fixed modexp reading huge numbers

* Enabled max_code_size test

* Review fixes

* Updated pairing pricing

* missing commas (style)

* Update test.rs

* Small improvements

* eip161abc