Initial: Offchain Workers (#1942)

* Refactor state-machine stuff.

* Fix tests.

* WiP

* WiP2

* Service support for offchain workers.

* Service support for offchain workers.

* Testing offchain worker.

* Initial version working.

* Pass side effects in call.

* Pass OffchainExt in context.

* Submit extrinsics to the pool.

* Support inherents.

* Insert to inherents pool.

* Inserting to the pool asynchronously.

* Add test to offchain worker.

* Implement convenience syntax for modules.

* Dispatching offchain worker through executive.

* Fix offchain test.

* Remove offchain worker from timestamp.

* Update Cargo.lock.

* Address review comments.

* Use latest patch version for futures.

* Add CLI parameter for offchain worker.

* Fix compilation.

* Fix test.

* Fix extrinsics format for tests.

* Fix RPC test.

* Bump spec version.

* Fix executive.

* Fix support macro.

* Address grumbles.

* Bump runtime

substrate/node/runtime/src/lib.rs

@@ -58,8 +58,8 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	spec_name: create_runtime_str!("node"),
 	impl_name: create_runtime_str!("substrate-node"),
 	authoring_version: 10,
-	spec_version: 42,
-	impl_version: 42,
+	spec_version: 43,
+	impl_version: 43,
 	apis: RUNTIME_API_VERSIONS,
 };
 
@@ -288,6 +288,12 @@ impl_runtime_apis! {
 		}
 	}
 
+	impl offchain_primitives::OffchainWorkerApi<Block> for Runtime {
+		fn offchain_worker(number: NumberFor<Block>) {
+			Executive::offchain_worker(number)
+		}
+	}
+
 	impl fg_primitives::GrandpaApi<Block> for Runtime {
 		fn grandpa_pending_change(digest: &DigestFor<Block>)
 			-> Option<ScheduledChange<NumberFor<Block>>>