* move common forks and parameters to common params
* port specs over to new format
* fix RPC tests
* parity-machine skeleton
* remove block type
* extract out ethereum-specific methods into EthereumMachine
* beginning to integrate Machine into engines. dealing with stale transitions in Ethash
* initial porting to machine
* move block reward back into engine
* abstract block reward logic
* move last hash and DAO HF logic into machine
* begin making engine function parameters generic
* abstract epoch verifier and ethash block reward logic
* instantiate special ethereummachine for ethash in spec
* optional full verification in verify_block_family
* re-instate tx_filter in a way that works for all engines
* fix warnings
* fix most tests, further generalize engine trait
* uncomment nullengine, get ethcore tests compiling
* fix warnings
* update a bunch of specs
* re-enable engine signer, validator set, and transition handler
* migrate basic_authority engine
* move last hashes into executedblock
* port tendermint
* make all ethcore tests pass
* json-tests compilation
* fix RPC tests: change in gas limit for new block changed PoW hash
* fix minor grumbles
* validate chainspecs
* fix broken import
* fix transaction verification for pre-homestead
* The front-end for each hard-fork, also EIP-160.
* Address EIP161 a/c
* Include EIP-161b
* EIP-161 part d.
* Fix test build.
* Fix one test, add another.
* Fix use of bloom & renaming.
* Initial groundwork for EIP-155
* Fix minor bug.
* Fix all tests finally.
* Rest of EIP-155.
* Add tests for EIP-155 algorithm.
Update transaction tests validation.
* Minor reformat.
* Address grumbles.
* Remove unused code.
* Fix SUICIDE gas mechanism and add consensus tests.
* Remove commented code.
* Set Frontier hardfork block number
* Fix warning.
* Transaction tests,
