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/core/inherents/src/lib.rs

@@ -31,6 +31,7 @@
 //! information on how that is done.
 
 #![cfg_attr(not(feature = "std"), no_std)]
+#![warn(missing_docs)]
 
 use parity_codec as codec;
 use codec::{Encode, Decode};
@@ -43,6 +44,9 @@ use parking_lot::RwLock;
 #[cfg(feature = "std")]
 use std::{sync::Arc, format};
 
+#[cfg(feature = "std")]
+pub mod pool;
+
 pub use runtime_primitives::RuntimeString;
 
 /// An identifier for an inherent.