* updater: refactor updater flow into state machine
* updater: delay update randomly within max range
* updater: configurable update delay
* updater: split polling and updater state machine step
* updater: drop state to avoid deadlocking
* updater: fix fetch backoff
* updater: fix overflow in update delay calculation
* updater: configurable update check frequency
* updater: fix update policy frequency comparison
* updater: use lazy_static for platform and platform_id_hash
* updater: refactor operations contract calls into OperationsClient
* updater: make updater generic over operations and fetch client
* updater: fix compilation
* updater: add testing infrastructure and minimal test
* updater: fix minor grumbles
* updater: add test for successful updater flow
* updater: add test for update delay
* updater: add test for update check frequency
* updater: mock time and rng for deterministic tests
* updater: test backoff on failure
* updater: add test for backoff short-circuit on new release
* updater: refactor to increase readability
* updater: cap maximum backoff to one month
* updater: add test for detecting already downloaded update
* updater: add test for updater disable on fatal errors
* updater: add test for pending outdated fetch
* updater: test auto install of updates
* updater: add test for capability updates
* updater: fix capability update
* updater: use ethabi to create event topic filter
* updater: decrease maximum backoff to 1 day
* updater: cap maximum update delay with upcoming fork block number
* updater: receive state mutex guard in updater_step
* updater: overload execute_upgrade to take state mutex guard
* updater: remove unnecessary clone of latest operations info
* updater: remove latest operations info clone when triggering fetch
* Refactor updater to use ethabi-derive
* Grumble: do_call type alias
* Empty commit to trigger test re-run
* migration to ethabi-5.0
* migration to ethabi-5.0 in progress
* use ethabi_deriven to generate TransactAcl contract
* use ethabi_deriven to generate Registry contract
* hash-fetch uses ethabi_derive, removed retain cycle from updater, fixed#7720
* node-filter crate uses ethabi_derive to generate peer_set contract interface
* use LruCache in node-filter instead of HashMap
* validator_set engine uses ethabi_derive
* ethcore does not depend on native_contracts
* miner does no depend on native_contracts
* secret_store does not use native_contracts (in progress)
* removed native-contracts
* ethcore and updater does not depend on futures
* updated ethereum-types
* fixed all warnings caused by using new version of ethereum-types
* updated ethabi_derive && ethabi_contract to get rid of warnings
* removed another retain cycle in updater, fixed following minor version on update
* moved contracts out of native_contracts res
* updated ethabi_contract
* fixed failing test
* fixed failing test
* there is no need to create two contracts of the same kind any more
* simplify updater::ReleaseTrack conversion into u8 and add several tests for it
* applied review suggestions
* applied review suggestions
