* separate modules for consensus snapshot chunks
* bulk of authority warp logic
* finish authority warp implementation
* squash warnings and enable authority snapshot mode
* test harness for PoA
* fiddle with harness
* epoch generation proof fixes
* update constructor code
* store epoch transition proof after block commit
* basic snap and restore test
* use keyvaluedb in state restoration
* decompress chunks
* fix encoding issues
* fixed-to-contract-to-contract test
* implement ancient block import
* restore genesis transition in PoW snapshot
* add format version method to snapshot components
* supported version numbers in snapshot_components
* allow returning of ancient epoch transitions
* genesis hash mismatch check
* remove commented code
* make validator set aware of various states
* fix updater build
* clean up contract call
* failing sync test
* adjust tests
* nicer indent [ci skip]
* revert bound divisor
* remove register_account_provider
* build rpc module
* new dummy client
* common EngineSigner struct
* from -> into
* initial report via call
* separate safe from regular contract
* transact_contract
* fix build
* return Signature, docs
* add sign method to some engines
* add safeContract spec
* update specs to new contracts
* use AuthorityRound for contract spec
* add more reporting
* add reporting test
* use gas floor
* shorter
