Add caching to BeaconState.

Removes CachingBeaconState

beacon_node/beacon_chain/src/checkpoint.rs

@@ -3,7 +3,7 @@ use types::{BeaconBlock, BeaconState, Hash256};
 
 /// Represents some block and it's associated state. Generally, this will be used for tracking the
 /// head, justified head and finalized head.
-#[derive(PartialEq, Clone, Serialize)]
+#[derive(Clone, Serialize)]
 pub struct CheckPoint {
     pub beacon_block: BeaconBlock,
     pub beacon_block_root: Hash256,