Clean up the basic-authorship crate (#3206)

* Switch consensus-common to new futures

* Fix tests

* More tests fixing

* Make Proposer, OnSlot and SyncOracle mut

* Make the Environment mut as well

* Fix test

* Fix Babe tests

* Babe fixes

* Fix CLI service tests

* Fix Babe tests

* Remove unnecessary trait bound

* Inline the code of BlockBuilder and AuthoringApi

* Remove warning lint

* Bounds simplification

* Imports simplification

* Don't panic on bad generated block

* Code style

* Add doc example

* Remove dependency on aura

* Order dependencies alphabetically

* Minor style

substrate/core/basic-authorship/src/lib.rs

@@ -15,9 +15,44 @@
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
 //! Basic implementation of block-authoring logic.
-
-#![warn(unused_extern_crates)]
+//!
+//! # Example
+//!
+//! ```
+//! # use substrate_basic_authorship::ProposerFactory;
+//! # use consensus_common::{Environment, Proposer};
+//! # use runtime_primitives::generic::BlockId;
+//! # use std::{sync::Arc, time::Duration};
+//! # use test_client::{self, runtime::{Extrinsic, Transfer}, AccountKeyring};
+//! # use transaction_pool::txpool::{self, Pool as TransactionPool};
+//! # let client = Arc::new(test_client::new());
+//! # let chain_api = transaction_pool::ChainApi::new(client.clone());
+//! # let txpool = Arc::new(TransactionPool::new(Default::default(), chain_api));
+//! // The first step is to create a `ProposerFactory`.
+//! let mut proposer_factory = ProposerFactory {
+//! 	client: client.clone(),
+//! 	transaction_pool: txpool.clone(),
+//! };
+//!
+//! // From this factory, we create a `Proposer`.
+//! let mut proposer = proposer_factory.init(
+//! 	&client.header(&BlockId::number(0)).unwrap().unwrap(),
+//! ).unwrap();
+//!
+//! // This `Proposer` allows us to create a block proposition.
+//! // The proposer will grab transactions from the transaction pool, and put them into the block.
+//! let future = proposer.propose(
+//! 	Default::default(),
+//! 	Default::default(),
+//! 	Duration::from_secs(2)
+//! );
+//!
+//! // We wait until the proposition is performed.
+//! let block = futures::executor::block_on(future).unwrap();
+//! println!("Generated block: {:?}", block);
+//! ```
+//!
 
 mod basic_authorship;
 
-pub use crate::basic_authorship::{ProposerFactory, BlockBuilder, AuthoringApi, Proposer};
+pub use crate::basic_authorship::{ProposerFactory, Proposer};