Bulk signature verification (#507)

* Add basic block processing benches

* Start reviving state processing benches

* Fix old block builders

* Add optimization for faster pubkey add

* Tidy benches, add another

* Add extra block processing bench

* Start working on faster BLS scheme

* Add partially complete sig verify optimization

* Add .gitignore to state processing

* Add progress on faster signature verification

* Fix SignatureSet for fake_crypto

* Tidy attester slashings sig set

* Tidy bulk signature verifier

* Refactor signature sets to be cleaner

* Start threading SignatureStrategy through code

* Add (empty) test dir

* Move BenchingBlockBuilder

* Add initial block signature verification tests

* Add tests for bulk signature verification

* Start threading SignatureStrategy in block proc.

* Refactor per_block_processing errors

* Use sig set tuples instead of lists of two

* Remove dead code

* Thread VerifySignatures through per_block_processing

* Add bulk signature verification

* Introduce parallel bulk signature verification

* Expand state processing benches

* Fix additional compile errors

* Fix issue where par iter chunks is 0

* Update milagro_bls dep

* Remove debugs, code fragment in beacon chain

* Tidy, add comments to block sig verifier

* Fix various PR comments

* Add block_root option to per_block_processing

* Fix comment in block signature verifier

* Fix comments from PR review

* Remove old comment

* Fix comment

beacon_node/beacon_chain/Cargo.toml

@@ -11,6 +11,7 @@ lazy_static = "1.3.0"
 lighthouse_metrics = { path = "../../eth2/utils/lighthouse_metrics" }
 log = "0.4"
 operation_pool = { path = "../../eth2/operation_pool" }
+rayon = "1.0"
 serde = "1.0"
 serde_derive = "1.0"
 slog = { version = "^2.2.3" , features = ["max_level_trace"] }