Refactor sr_primitives. (#3214)

* refactor sr_primitives.

* Fix try build error.

* Line-width

* Ui test.

* Final fixes.

* Fix build again.

* bring back ui test.

* Fix unsigned import.

* Another ui fix.

* Also refactor substrate-primitives

* Fix benchmarks.

* Fix doc test.

* fix doc tests

substrate/core/consensus/aura/primitives/src/lib.rs

@@ -21,7 +21,7 @@
 use parity_codec::{Encode, Decode, Codec};
 use substrate_client::decl_runtime_apis;
 use rstd::vec::Vec;
-use runtime_primitives::ConsensusEngineId;
+use sr_primitives::ConsensusEngineId;
 
 /// The `ConsensusEngineId` of AuRa.
 pub const AURA_ENGINE_ID: ConsensusEngineId = [b'a', b'u', b'r', b'a'];