Consensus Engines Implementation: Aura (#911)

* Generalize BlockImport

 - move ImportBlock, BlockOrigin, ImportResult into shared sr-primitives
 - let Consensus provide  and  traits again
 - update consensus traits to latest development
 - implement traits on client::Client, test_client::TestClient
 - update RHD to use the new import_block API

* Move ImportBlock into consensus-common
* Send import notification in aura tests
* Integrating aura into service
* Make Signatures more generic
* Aura Block Production with the given key
* run aura on the thread pool
* start at exact step start in aura
* Add needed wasm blob, in leiu of better solutions.
* Make API ids consistent with traits and bring upstream for sharing.
* Add decrease_free_balance to Balances module
* Encode `Metadata` once instead of two times
* Bitops include xor
* Upgrade key module.
* Default pages to somewhat bigger.
* Introduce upgrade key into node
* Add `Created` event

substrate/core/client/src/lib.rs

@@ -26,6 +26,7 @@ extern crate parity_codec as codec;
 extern crate substrate_primitives as primitives;
 extern crate sr_primitives as runtime_primitives;
 extern crate substrate_state_machine as state_machine;
+extern crate substrate_consensus_common as consensus;
 #[cfg(test)] extern crate substrate_keyring as keyring;
 #[cfg(test)] extern crate substrate_test_client as test_client;
 #[macro_use] extern crate substrate_telemetry;
@@ -63,8 +64,8 @@ pub use call_executor::{CallResult, CallExecutor, LocalCallExecutor};
 pub use client::{
 	new_with_backend,
 	new_in_mem,
-	BlockBody, BlockStatus, BlockOrigin, ImportNotifications, FinalityNotifications, BlockchainEvents,
-	Client, ClientInfo, ChainHead, ImportResult, ImportBlock,
+	BlockBody, BlockStatus, ImportNotifications, FinalityNotifications, BlockchainEvents,
+	Client, ClientInfo, ChainHead,
 };
 pub use notifications::{StorageEventStream, StorageChangeSet};
 pub use state_machine::ExecutionStrategy;