* Some tiny modifications.
1. fix some typo in the comment.
2. sort the order of methods in 'impl state::Backend for StateDB`
* Remove the clone of code_cache, as it has been done in clone_basic.
* 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* updater: add test for pending outdated fetch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
* Replace Rlp with UntrustedRlp and unsafely unwrap
All Rlp methods return Result<_,DecoderError> now, so for this first
pass each will be marked with `expect("TODO")`. In the next pass we can
categorise figure out how to handle each case.
* Handle DecoderError for tendermint message
* Unwrap rlp results in TestBlockcChainClient
Rlp should be valid since created manually in tests
* Replace `use rlp::*` with explicit imports
* Remove rlp decode unwraps from light cli request
* Structured rlp encoding for curr best and latest in header chain
* Propogate decoder errors from send_packet
* Fix body uncles rlp index
* Use BodyView in sync and `expect` rlp errors
* Revert bbf28f removing original Rlp for this phase
This can be done again in the next phase, in order that we can leave the ethcore views unchanged
* Restore legacy Rlp and UntrustedRlp
Use legacy Rlp for ethcore views. Will redo replacing Rlp with UntrustedRlp in a subsequent PR
* Fix tests
* Replace boilerplate Encodable/Decodable with derive
* Use BlockView instead of Rlp, remove unwrap
* Remove rlp test_cli unwraps by using BlockView instead of Rlp directly
* Remove unneccesary change to use borrowed hash
* Construct sync block using new_from_header_and_body
* Very primitive test of the Client API
* [WIP] getting rid of request
* Add support for redirects.
* Remove CpuPool from `fetch::Client`.
* Adapt code to API changes and fix tests.
* Use reference counter to stop background thread.
On `clone` the counter is incremented, on `drop` decremented. Once 0 we
send `None` over the channel, expecting the background thread to end.
* Fix tests.
* Comment.
* Change expect messages.
* Use local test server for testing fetch client.
* Ensure max_size also in BodyReader.
* Replace `Condvar` with `sync_channel`.
* Re-export `url::Url` from `fetch` crate.
* Remove spaces.
* Use random ports in local test server.
