Publish ssz_types (and deps) to crates.io (#468)

* Rename `hashing` crate to `eth2_hashing`

* Add license, desc to eth2_hashing Cargo.toml

* Remove merkle root from eth2 hashing

* Remove old benches folder (zombied from old branch)

* Add docs to eth2_hashing

* Prepare tree_hash for publishing on crates.io

* Update deps to use crates.io instead of paths

* Update all crates to pull ssz from crates.io

* Remove cached_tree_hash, add patches to manifest

* Fix compile error in benches

* Remove unused code

* Fix fake_crypto compile error

tests/ef_tests/src/cases/ssz_static.rs

@@ -1,6 +1,5 @@
 use super::*;
 use crate::case_result::compare_result;
-use cached_tree_hash::CachedTreeHash;
 use serde_derive::Deserialize;
 use ssz::{Decode, Encode};
 use std::fmt::Debug;
@@ -103,7 +102,6 @@ where
         + PartialEq<T>
         + serde::de::DeserializeOwned
         + TreeHash
-        + CachedTreeHash
         + TestRandom,
 {
     // Verify we can decode SSZ in the same way we can decode YAML.