Add OptimizedLMDGhost fork choice rule and tests

eth2/fork_choice/src/lib.rs

@@ -23,6 +23,7 @@ extern crate types;
 pub mod bitwise_lmd_ghost;
 pub mod longest_chain;
 pub mod slow_lmd_ghost;
+pub mod optimized_lmd_ghost;
 
 use db::stores::BeaconBlockAtSlotError;
 use db::DBError;
@@ -31,6 +32,7 @@ use types::{BeaconBlock, ChainSpec, Hash256};
 pub use bitwise_lmd_ghost::BitwiseLMDGhost;
 pub use longest_chain::LongestChain;
 pub use slow_lmd_ghost::SlowLMDGhost;
+pub use optimized_lmd_ghost::OptimizedLMDGhost;
 
 /// Defines the interface for Fork Choices. Each Fork choice will define their own data structures
 /// which can be built in block processing through the `add_block` and `add_attestation` functions.
@@ -101,4 +103,6 @@ pub enum ForkChoiceAlgorithm {
     SlowLMDGhost,
     /// An optimised version of bitwise LMD-GHOST by Vitalik.
     BitwiseLMDGhost,
+    /// An optimised implementation of LMD ghost.
+    OptimizedLMDGhost
 }