Milestone 1 (#144)

* use best_finalized, prevent race

* make best_finalized_block an Option, should_vote_on bails on None

* Bump futures from 0.3.13 to 0.3.14

* Revert futures bump

* Revert "Revert futures bump"

This reverts commit a1b5e7e9bac526f2897ebfdfee7f02dd29a13ac5.

* Revert "Bump futures from 0.3.13 to 0.3.14"

This reverts commit a4e508b118ad2c4b52909d24143c284073961458.

* debug msg if the bail voting

* validator_set()

* local_id()

* get rid of worker state

* Apply review suggestions

* fix should_vote_on()

primitives/beefy/src/lib.rs

@@ -66,6 +66,9 @@ pub mod ecdsa {
 /// The `ConsensusEngineId` of BEEFY.
 pub const BEEFY_ENGINE_ID: sp_runtime::ConsensusEngineId = *b"BEEF";
 
+/// Authority set id starts with zero at genesis
+pub const GENESIS_AUTHORITY_SET_ID: u64 = 0;
+
 /// A typedef for validator set id.
 pub type ValidatorSetId = u64;