* kvdb-rocksdb: update to RocksDB 5.8.8
* kvdb-rocksdb: tune RocksDB options
* Switch to level-style compaction
* Increase default block size (16K), and use bigger blocks for HDDs (64K)
* Increase default file size base (64MB SSDs, 256MB HDDs)
* Create a single block cache shared across all column families
* Tune compaction settings using RocksDB helper functions, taking into account
memory budget spread across all columns
* Configure backgrounds jobs based on the number of CPUs
* Set some default recommended settings
* ethcore: remove unused config blockchain.db_cache_size
* parity: increase default value for db_cache_size
* kvdb-rocksdb: enable compression on all levels
* kvdb-rocksdb: set global db_write_bufer_size
* kvdb-rocksdb: reduce db_write_bufer_size to force earlier flushing
* kvdb-rocksdb: use master branch for rust-rocksdb dependency
* separate migration from util and make its dependencies into libs:
* snappy
* kvdb
* error
* common
* renamed common -> macros
* util error does not depend on snappy module
* ethsync does not depend on util nor ethcore_error
* nibbleslice and nibblevec merged with patricia_trie crate
* removed unused dependencies from util
* util journaldb traits does not need to be public
* util_error
* fixed ethcore compile error
* ignore .swo files
* Update chain.rs
* Optional offset and count added on client level
* Rpc interface extended
* Tests corrected
* Filtering code refactored a little bit
* Offset type was changed to usize
* Handling of block hash in offset added
* Offset reworked to number
* Trailing comma removed
* Import for Quantity type added
* Offset and count moved into filter object
* Lost comma removed
* Return empty vec instead of None in case of incorrect range
* 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
* generate proofs on newly-created state
* report only missed steps after first block
* dont report skipped if not signer
* test
* finality tracing and passing valid header to `commit_block`
* avoid proposing multiple times on the same step when validator set changes
* limit benign reports
* Ordering -> AtomicOrdering
* reinstate warning now that spam is reduced
* flush pending transition changes when necessary
* ensure epochs aren't re-zoomed on every block
* do more validation of imported headers in light client
* generalize informant with traits
* informant implementation for light client
* make comment into TODO
* fix broken test
* disable full checking of headers in light client in sync tests
