Optimizations, disable val client sync check & additional lcli tools (#834)

* Start adding interop genesis state to lcli

* Use more efficient method to generate genesis state

* Remove duplicate int_to_bytes32

* Add lcli command to change state genesis time

* Add option to allow VC to start with unsynced BN

* Set VC to do parallel key loading

* Don't default to dummy eth1 backend

* Add endpoint to dump operation pool

* Add metrics for op pool

* Remove state clone for slot notifier

* Add mem size approximation for tree hash cache

* Avoid cloning tree hash when getting head

* Fix failing API tests

* Address Michael's comments

* Add HashMap::from_par_iter

lcli/src/change_genesis_time.rs

@@ -0,0 +1,40 @@
+use clap::ArgMatches;
+use ssz::{Decode, Encode};
+use std::fs::File;
+use std::io::{Read, Write};
+use std::path::PathBuf;
+use types::{BeaconState, EthSpec};
+
+pub fn run<T: EthSpec>(matches: &ArgMatches) -> Result<(), String> {
+    let path = matches
+        .value_of("ssz-state")
+        .ok_or_else(|| "ssz-state not specified")?
+        .parse::<PathBuf>()
+        .map_err(|e| format!("Unable to parse ssz-state: {}", e))?;
+
+    let genesis_time = matches
+        .value_of("genesis-time")
+        .ok_or_else(|| "genesis-time not specified")?
+        .parse::<u64>()
+        .map_err(|e| format!("Unable to parse genesis-time: {}", e))?;
+
+    let mut state: BeaconState<T> = {
+        let mut file = File::open(&path).map_err(|e| format!("Unable to open file: {}", e))?;
+
+        let mut ssz = vec![];
+
+        file.read_to_end(&mut ssz)
+            .map_err(|e| format!("Unable to read file: {}", e))?;
+
+        BeaconState::from_ssz_bytes(&ssz).map_err(|e| format!("Unable to decode SSZ: {:?}", e))?
+    };
+
+    state.genesis_time = genesis_time;
+
+    let mut file = File::create(path).map_err(|e| format!("Unable to create file: {}", e))?;
+
+    file.write_all(&state.as_ssz_bytes())
+        .map_err(|e| format!("Unable to write to file: {}", e))?;
+
+    Ok(())
+}