Extract Machine from ethcore (#10949)

* Add client-traits crate
Move the BlockInfo trait to new crate

* New crate `machine`
Contains code extracted from ethcore that defines `Machine`, `Externalities` and other execution related code.

* Use new machine and client-traits crates in ethcore

* Use new crates machine and client-traits instead of ethcore where appropriate

* Fix tests

* Don't re-export so many types from ethcore::client

* Fixing more fallout from removing re-export

* fix test

* More fallout from not re-exporting types

* Add some docs

* cleanup

* import the macro edition style

* Tweak docs

* Add missing import

* remove unused ethabi_derive imports

* Use latest ethabi-contract

ethcore/sync/src/block_sync.rs

@@ -25,9 +25,10 @@ use ethereum_types::H256;
 use rlp::{self, Rlp};
 use types::{
 	BlockNumber,
+	block_status::BlockStatus,
+	ids::BlockId,
 	errors::{EthcoreError, BlockError, ImportError},
 };
-use ethcore::client::{BlockStatus, BlockId};
 use sync_io::SyncIo;
 use blocks::{BlockCollection, SyncBody, SyncHeader};
 use chain::BlockSet;